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path: root/drivers/scsi/hosts.c
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2023-09-23scsi: core: Use 32-bit hostnum in scsi_host_lookup()Tony Battersby
[ Upstream commit 62ec2092095b678ff89ce4ba51c2938cd1e8e630 ] Change scsi_host_lookup() hostnum argument type from unsigned short to unsigned int to match the type used everywhere else. Fixes: 6d49f63b415c ("[SCSI] Make host_no an unsigned int") Signed-off-by: Tony Battersby <tonyb@cybernetics.com> Link: https://lore.kernel.org/r/a02497e7-c12b-ef15-47fc-3f0a0b00ffce@cybernetics.com Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-03-17scsi: core: Remove the /proc/scsi/${proc_name} directory earlierBart Van Assche
[ Upstream commit fc663711b94468f4e1427ebe289c9f05669699c9 ] Remove the /proc/scsi/${proc_name} directory earlier to fix a race condition between unloading and reloading kernel modules. This fixes a bug introduced in 2009 by commit 77c019768f06 ("[SCSI] fix /proc memory leak in the SCSI core"). Fix the following kernel warning: proc_dir_entry 'scsi/scsi_debug' already registered WARNING: CPU: 19 PID: 27986 at fs/proc/generic.c:376 proc_register+0x27d/0x2e0 Call Trace: proc_mkdir+0xb5/0xe0 scsi_proc_hostdir_add+0xb5/0x170 scsi_host_alloc+0x683/0x6c0 sdebug_driver_probe+0x6b/0x2d0 [scsi_debug] really_probe+0x159/0x540 __driver_probe_device+0xdc/0x230 driver_probe_device+0x4f/0x120 __device_attach_driver+0xef/0x180 bus_for_each_drv+0xe5/0x130 __device_attach+0x127/0x290 device_initial_probe+0x17/0x20 bus_probe_device+0x110/0x130 device_add+0x673/0xc80 device_register+0x1e/0x30 sdebug_add_host_helper+0x1a7/0x3b0 [scsi_debug] scsi_debug_init+0x64f/0x1000 [scsi_debug] do_one_initcall+0xd7/0x470 do_init_module+0xe7/0x330 load_module+0x122a/0x12c0 __do_sys_finit_module+0x124/0x1a0 __x64_sys_finit_module+0x46/0x50 do_syscall_64+0x38/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 Link: https://lore.kernel.org/r/20230210205200.36973-3-bvanassche@acm.org Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Yi Zhang <yi.zhang@redhat.com> Cc: stable@vger.kernel.org Fixes: 77c019768f06 ("[SCSI] fix /proc memory leak in the SCSI core") Reported-by: Yi Zhang <yi.zhang@redhat.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-10-27scsi: core: Fix shost->cmd_per_lun calculation in scsi_add_host_with_dma()Dexuan Cui
commit 50b6cb3516365cb69753b006be2b61c966b70588 upstream. After commit ea2f0f77538c ("scsi: core: Cap scsi_host cmd_per_lun at can_queue"), a 416-CPU VM running on Hyper-V hangs during boot because the hv_storvsc driver sets scsi_driver.can_queue to an integer value that exceeds SHRT_MAX, and hence scsi_add_host_with_dma() sets shost->cmd_per_lun to a negative "short" value. Use min_t(int, ...) to work around the issue. Link: https://lore.kernel.org/r/20211008043546.6006-1-decui@microsoft.com Fixes: ea2f0f77538c ("scsi: core: Cap scsi_host cmd_per_lun at can_queue") Cc: stable@vger.kernel.org Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: John Garry <john.garry@huawei.com> Signed-off-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-20scsi: core: Cap scsi_host cmd_per_lun at can_queueJohn Garry
[ Upstream commit ea2f0f77538c50739b9fb4de4700cee5535e1f77 ] The sysfs handling function sdev_store_queue_depth() enforces that the sdev queue depth cannot exceed shost can_queue. The initial sdev queue depth comes from shost cmd_per_lun. However, the LLDD may manually set cmd_per_lun to be larger than can_queue, which leads to an initial sdev queue depth greater than can_queue. Such an issue was reported in [0], which caused a hang. That has since been fixed in commit fc09acb7de31 ("scsi: scsi_debug: Fix cmd_per_lun, set to max_queue"). Stop this possibly happening for other drivers by capping shost cmd_per_lun at shost can_queue. [0] https://lore.kernel.org/linux-scsi/YHaez6iN2HHYxYOh@T590/ Link: https://lore.kernel.org/r/1621434662-173079-1-git-send-email-john.garry@huawei.com Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Signed-off-by: John Garry <john.garry@huawei.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-20scsi: core: Fix bad pointer dereference when ehandler kthread is invalidTyrel Datwyler
commit 93aa71ad7379900e61c8adff6a710a4c18c7c99b upstream. Commit 66a834d09293 ("scsi: core: Fix error handling of scsi_host_alloc()") changed the allocation logic to call put_device() to perform host cleanup with the assumption that IDA removal and stopping the kthread would properly be performed in scsi_host_dev_release(). However, in the unlikely case that the error handler thread fails to spawn, shost->ehandler is set to ERR_PTR(-ENOMEM). The error handler cleanup code in scsi_host_dev_release() will call kthread_stop() if shost->ehandler != NULL which will always be the case whether the kthread was successfully spawned or not. In the case that it failed to spawn this has the nasty side effect of trying to dereference an invalid pointer when kthread_stop() is called. The following splat provides an example of this behavior in the wild: scsi host11: error handler thread failed to spawn, error = -4 Kernel attempted to read user page (10c) - exploit attempt? (uid: 0) BUG: Kernel NULL pointer dereference on read at 0x0000010c Faulting instruction address: 0xc00000000818e9a8 Oops: Kernel access of bad area, sig: 11 [#1] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries Modules linked in: ibmvscsi(+) scsi_transport_srp dm_multipath dm_mirror dm_region hash dm_log dm_mod fuse overlay squashfs loop CPU: 12 PID: 274 Comm: systemd-udevd Not tainted 5.13.0-rc7 #1 NIP: c00000000818e9a8 LR: c0000000089846e8 CTR: 0000000000007ee8 REGS: c000000037d12ea0 TRAP: 0300 Not tainted (5.13.0-rc7) MSR: 800000000280b033 &lt;SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE&gt; CR: 28228228 XER: 20040001 CFAR: c0000000089846e4 DAR: 000000000000010c DSISR: 40000000 IRQMASK: 0 GPR00: c0000000089846e8 c000000037d13140 c000000009cc1100 fffffffffffffffc GPR04: 0000000000000001 0000000000000000 0000000000000000 c000000037dc0000 GPR08: 0000000000000000 c000000037dc0000 0000000000000001 00000000fffff7ff GPR12: 0000000000008000 c00000000a049000 c000000037d13d00 000000011134d5a0 GPR16: 0000000000001740 c0080000190d0000 c0080000190d1740 c000000009129288 GPR20: c000000037d13bc0 0000000000000001 c000000037d13bc0 c0080000190b7898 GPR24: c0080000190b7708 0000000000000000 c000000033bb2c48 0000000000000000 GPR28: c000000046b28280 0000000000000000 000000000000010c fffffffffffffffc NIP [c00000000818e9a8] kthread_stop+0x38/0x230 LR [c0000000089846e8] scsi_host_dev_release+0x98/0x160 Call Trace: [c000000033bb2c48] 0xc000000033bb2c48 (unreliable) [c0000000089846e8] scsi_host_dev_release+0x98/0x160 [c00000000891e960] device_release+0x60/0x100 [c0000000087e55c4] kobject_release+0x84/0x210 [c00000000891ec78] put_device+0x28/0x40 [c000000008984ea4] scsi_host_alloc+0x314/0x430 [c0080000190b38bc] ibmvscsi_probe+0x54/0xad0 [ibmvscsi] [c000000008110104] vio_bus_probe+0xa4/0x4b0 [c00000000892a860] really_probe+0x140/0x680 [c00000000892aefc] driver_probe_device+0x15c/0x200 [c00000000892b63c] device_driver_attach+0xcc/0xe0 [c00000000892b740] __driver_attach+0xf0/0x200 [c000000008926f28] bus_for_each_dev+0xa8/0x130 [c000000008929ce4] driver_attach+0x34/0x50 [c000000008928fc0] bus_add_driver+0x1b0/0x300 [c00000000892c798] driver_register+0x98/0x1a0 [c00000000810eb60] __vio_register_driver+0x80/0xe0 [c0080000190b4a30] ibmvscsi_module_init+0x9c/0xdc [ibmvscsi] [c0000000080121d0] do_one_initcall+0x60/0x2d0 [c000000008261abc] do_init_module+0x7c/0x320 [c000000008265700] load_module+0x2350/0x25b0 [c000000008265cb4] __do_sys_finit_module+0xd4/0x160 [c000000008031110] system_call_exception+0x150/0x2d0 [c00000000800d35c] system_call_common+0xec/0x278 Fix this be nulling shost->ehandler when the kthread fails to spawn. Link: https://lore.kernel.org/r/20210701195659.3185475-1-tyreld@linux.ibm.com Fixes: 66a834d09293 ("scsi: core: Fix error handling of scsi_host_alloc()") Cc: stable@vger.kernel.org Reviewed-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-06-16scsi: core: Only put parent device if host state differs from SHOST_CREATEDMing Lei
commit 1e0d4e6225996f05271de1ebcb1a7c9381af0b27 upstream. get_device(shost->shost_gendev.parent) is called after host state has switched to SHOST_RUNNING. scsi_host_dev_release() shouldn't release the parent device if host state is still SHOST_CREATED. Link: https://lore.kernel.org/r/20210602133029.2864069-5-ming.lei@redhat.com Cc: Bart Van Assche <bvanassche@acm.org> Cc: John Garry <john.garry@huawei.com> Cc: Hannes Reinecke <hare@suse.de> Tested-by: John Garry <john.garry@huawei.com> Reviewed-by: John Garry <john.garry@huawei.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-06-16scsi: core: Put .shost_dev in failure path if host state changes to RUNNINGMing Lei
commit 11714026c02d613c30a149c3f4c4a15047744529 upstream. scsi_host_dev_release() only frees dev_name when host state is SHOST_CREATED. After host state has changed to SHOST_RUNNING, scsi_host_dev_release() no longer cleans up. Fix this by doing a put_device(&shost->shost_dev) in the failure path when host state is SHOST_RUNNING. Move get_device(&shost->shost_gendev) before device_add(&shost->shost_dev) so that scsi_host_cls_release() can do a put on this reference. Link: https://lore.kernel.org/r/20210602133029.2864069-4-ming.lei@redhat.com Cc: Bart Van Assche <bvanassche@acm.org> Cc: Hannes Reinecke <hare@suse.de> Reported-by: John Garry <john.garry@huawei.com> Tested-by: John Garry <john.garry@huawei.com> Reviewed-by: John Garry <john.garry@huawei.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-06-16scsi: core: Fix error handling of scsi_host_alloc()Ming Lei
commit 66a834d092930cf41d809c0e989b13cd6f9ca006 upstream. After device is initialized via device_initialize(), or its name is set via dev_set_name(), the device has to be freed via put_device(). Otherwise device name will be leaked because it is allocated dynamically in dev_set_name(). Fix the leak by replacing kfree() with put_device(). Since scsi_host_dev_release() properly handles IDA and kthread removal, remove special-casing these from the error handling as well. Link: https://lore.kernel.org/r/20210602133029.2864069-2-ming.lei@redhat.com Cc: Bart Van Assche <bvanassche@acm.org> Cc: John Garry <john.garry@huawei.com> Cc: Hannes Reinecke <hare@suse.de> Tested-by: John Garry <john.garry@huawei.com> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: John Garry <john.garry@huawei.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-08-27Revert "scsi: core: avoid host-wide host_busy counter for scsi_mq"Ming Lei
This reverts commit 328728630d9f2bf14b82ca30b5e47489beefe361. There is fundamental issue in commit 328728630d9f2bf1 (scsi: core: avoid host-wide host_busy counter for scsi_mq) because SCSI's host busy counter may not be same with counter of blk-mq's inflight tags, especially in case of none io scheduler. We may switch to other approach for addressing this scsi_mq's performance issue, such as percpu counter or kind of ways, so revert this commit first for fixing this kind of issue in EH path, as reported by Jens. Cc: Omar Sandoval <osandov@fb.com>, Cc: "Martin K. Petersen" <martin.petersen@oracle.com>, Cc: James Bottomley <james.bottomley@hansenpartnership.com>, Cc: Christoph Hellwig <hch@lst.de>, Cc: Don Brace <don.brace@microsemi.com> Cc: Kashyap Desai <kashyap.desai@broadcom.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Hannes Reinecke <hare@suse.de> Cc: Laurence Oberman <loberman@redhat.com> Cc: Bart Van Assche <bart.vanassche@wdc.com> Cc: Jens Axboe <axboe@kernel.dk> Reported-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2018-06-26scsi: core: avoid host-wide host_busy counter for scsi_mqMing Lei
It isn't necessary to check the host depth in scsi_queue_rq() any more since it has been respected by blk-mq before calling scsi_queue_rq() via getting driver tag. Lots of LUNs may attach to same host and per-host IOPS may reach millions, so we should avoid expensive atomic operations on the host-wide counter in the IO path. This patch implements scsi_host_busy() via blk_mq_tagset_busy_iter() for reading the count of busy IOs for scsi_mq. It is observed that IOPS is increased by 15% in IO test on scsi_debug (32 LUNs, 32 submit queues, 1024 can_queue, libaio/dio) in a dual-socket system. [mkp: clarified commit message] Cc: Omar Sandoval <osandov@fb.com>, Cc: "Martin K. Petersen" <martin.petersen@oracle.com>, Cc: James Bottomley <james.bottomley@hansenpartnership.com>, Cc: Christoph Hellwig <hch@lst.de>, Cc: Don Brace <don.brace@microsemi.com> Cc: Kashyap Desai <kashyap.desai@broadcom.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Hannes Reinecke <hare@suse.de> Cc: Laurence Oberman <loberman@redhat.com> Cc: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2018-06-26scsi: read host_busy via scsi_host_busy()Ming Lei
No functional change. Just introduce scsi_host_busy() and replace the direct read of scsi_host->host_busy with this new API. Cc: Omar Sandoval <osandov@fb.com>, Cc: "Martin K. Petersen" <martin.petersen@oracle.com>, Cc: James Bottomley <james.bottomley@hansenpartnership.com>, Cc: Christoph Hellwig <hch@lst.de>, Cc: Don Brace <don.brace@microsemi.com> Cc: Kashyap Desai <kashyap.desai@broadcom.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Hannes Reinecke <hare@suse.de> Cc: Laurence Oberman <loberman@redhat.com> Cc: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2018-04-09scsi: core: remove redundant assignment to shost->use_blk_mqColin Ian King
The first assignment to shost->use_blk_mq is redundant as it is overwritten by the following statement. Remove this redundant code. Detected by CoverityScan, CID#1466993 ("Unused value") Signed-off-by: Colin Ian King <colin.king@canonical.com> Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2018-04-03Merge branch 'fixes' into miscJames Bottomley
Somewhat nasty merge due to conflicts between "33b28357dd00 scsi: qla2xxx: Fix Async GPN_FT for FCP and FC-NVMe scan" and "2b5b96473efc scsi: qla2xxx: Fix FC-NVMe LUN discovery" Merge is non-trivial and has been verified by Qlogic (Cavium) Signed-off-by: James E.J. Bottomley <jejb@linux.vnet.ibm.com>
2018-03-19scsi: remove the old scsi_module.c initialization modelChristoph Hellwig
After more than 15 years all users of this legacy interface are finally gone. Rest in peace! Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2018-03-19scsi: core: unexport scsi_host_set_stateChristoph Hellwig
This function is only used inside the SCSI midlayer, so remove the export for it. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2018-03-14scsi: core: introduce force_blk_mqMing Lei
This patch introduces 'force_blk_mq' to the scsi_host_template so that drivers that have no desire to support the legacy I/O path can signal blk-mq only support. [mkp: commit desc] Cc: Omar Sandoval <osandov@fb.com>, Cc: "Martin K. Petersen" <martin.petersen@oracle.com>, Cc: James Bottomley <james.bottomley@hansenpartnership.com>, Cc: Christoph Hellwig <hch@lst.de>, Cc: Don Brace <don.brace@microsemi.com> Cc: Kashyap Desai <kashyap.desai@broadcom.com> Cc: Mike Snitzer <snitzer@redhat.com> Cc: Laurence Oberman <loberman@redhat.com> Signed-off-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2018-03-01scsi: core: Avoid that ATA error handling can trigger a kernel hang or oopsBart Van Assche
Avoid that the recently introduced call_rcu() call in the SCSI core triggers a double call_rcu() call. Reported-by: Natanael Copa <ncopa@alpinelinux.org> Reported-by: Damien Le Moal <damien.lemoal@wdc.com> References: https://bugzilla.kernel.org/show_bug.cgi?id=198861 Fixes: 3bd6f43f5cb3 ("scsi: core: Ensure that the SCSI error handler gets woken up") Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Reviewed-by: Damien Le Moal <damien.lemoal@wdc.com> Tested-by: Damien Le Moal <damien.lemoal@wdc.com> Cc: Natanael Copa <ncopa@alpinelinux.org> Cc: Damien Le Moal <damien.lemoal@wdc.com> Cc: Alexandre Oliva <oliva@gnu.org> Cc: Pavel Tikhomirov <ptikhomirov@virtuozzo.com> Cc: Hannes Reinecke <hare@suse.com> Cc: Johannes Thumshirn <jthumshirn@suse.de> Cc: <stable@vger.kernel.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2018-02-13scsi: core: Move the eh_deadline module parameter definitionBart Van Assche
The eh_deadline definition occurs in the middle of the code for releasing a host. Avoid splitting the host release code by moving the definition of the eh_deadline parameter to the top of the hosts.c source file. Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.com> Cc: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2017-12-07scsi: core: Ensure that the SCSI error handler gets woken upBart Van Assche
If scsi_eh_scmd_add() is called concurrently with scsi_host_queue_ready() while shost->host_blocked > 0 then it can happen that neither function wakes up the SCSI error handler. Fix this by making every function that decreases the host_busy counter wake up the error handler if necessary and by protecting the host_failed checks with the SCSI host lock. Reported-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com> References: https://marc.info/?l=linux-kernel&m=150461610630736 Fixes: commit 746650160866 ("scsi: convert host_busy to atomic_t") Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Reviewed-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com> Tested-by: Stuart Hayes <stuart.w.hayes@gmail.com> Cc: Konstantin Khorenko <khorenko@virtuozzo.com> Cc: Stuart Hayes <stuart.w.hayes@gmail.com> Cc: Pavel Tikhomirov <ptikhomirov@virtuozzo.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.com> Cc: Johannes Thumshirn <jthumshirn@suse.de> Cc: <stable@vger.kernel.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2017-09-05scsi: Remove Scsi_Host.uspace_req_qBart Van Assche
A patch I wrote myself several years ago removed SCSI target support from the code under drivers/scsi. That patch removed the code that sets uspace_req_q to a non-NULL value. Hence also remove the code that depends on uspace_req_q != NULL. References: commit 066465251303 ("tgt: removal") Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.de> Cc: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2017-01-27scsi: allocate scsi_cmnd structures as part of struct requestChristoph Hellwig
Rely on the new block layer functionality to allocate additional driver specific data behind struct request instead of implementing it in SCSI itѕelf. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2017-01-27scsi: respect unchecked_isa_dma for blk-mqChristoph Hellwig
Currently blk-mq always allocates the sense buffer using normal GFP_KERNEL allocation. Refactor the cmd pool code to split the cmd and sense allocation and share the code to allocate the sense buffers as well as the sense buffer slab caches between the legacy and blk-mq path. Note that this switches to lazy allocation of the sense slab caches - the slab caches (not the actual allocations) won't be destroy until the scsi module is unloaded instead of keeping track of hosts using them. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Acked-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <axboe@fb.com>
2016-10-07Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsiLinus Torvalds
Pull SCSI updates from James Bottomley: "This update includes the usual round of major driver updates (hpsa, be2iscsi, hisi_sas, zfcp, cxlflash). There's a new incarnation of hpsa called smartpqi for which a driver is added, there's some cleanup work of the ibm vscsi target and updates to libfc, plus a whole host of minor fixes and updates and finally the removal of several ISA drivers which seem not to have been used for years" * tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (173 commits) scsi: mvsas: Mark symbols static where possible scsi: pm8001: Mark symbols static where possible scsi: arcmsr: Simplify user_len checking scsi: fcoe: fix off by one in eth2fc_speed() scsi: dtc: remove from tree scsi: t128: remove from tree scsi: pas16: remove from tree scsi: u14-34f: remove from tree scsi: ultrastor: remove from tree scsi: in2000: remove from tree scsi: wd7000: remove from tree scsi: scsi_dh_alua: Fix memory leak in alua_rtpg() scsi: lpfc: Mark symbols static where possible scsi: hpsa: correct call to hpsa_do_reset scsi: ufs: Get a TM service response from the correct offset scsi: ibmvfc: Fix I/O hang when port is not mapped scsi: megaraid_sas: clean function declarations in megaraid_sas_base.c up scsi: ipr: Remove redundant messages at adapter init time scsi: ipr: Don't log unnecessary 9084 error details scsi: smartpqi: raid bypass lba calculation fix ...
2016-09-26scsi: Avoid that toggling use_blk_mq triggers a memory leakBart Van Assche
This patch avoids that the following memory leak is triggered if use_blk_mq is disabled after a SCSI host has been allocated by the ib_srp driver and before the same SCSI host is freed: unreferenced object 0xffff8803a168c568 (size 256): backtrace: [<ffffffff81620c95>] kmemleak_alloc+0x45/0xa0 [<ffffffff811bb104>] __kmalloc_node+0x1e4/0x400 [<ffffffff81309fe4>] blk_mq_alloc_tag_set+0xb4/0x230 [<ffffffff814731b7>] scsi_mq_setup_tags+0xc7/0xd0 [<ffffffff81469c26>] scsi_add_host_with_dma+0x216/0x2d0 [<ffffffffa064bef5>] srp_create_target+0xe55/0x13d0 [ib_srp] [<ffffffff8143ce23>] dev_attr_store+0x13/0x20 [<ffffffff8125f030>] sysfs_kf_write+0x40/0x50 [<ffffffff8125e397>] kernfs_fop_write+0x137/0x1c0 [<ffffffff811d8c13>] __vfs_write+0x23/0x140 [<ffffffff811d92e0>] vfs_write+0xb0/0x190 [<ffffffff811da5b4>] SyS_write+0x44/0xa0 [<ffffffff8162c8a5>] entry_SYSCALL_64_fastpath+0x18/0xa8 Fixes: 9aa9cc4221f5 ("scsi: remove the disable_blk_mq host flag") Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Martin K. Petersen <martin.petersen@oracle.com> Cc: <stable@vger.kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2016-08-25scsi: configure runtime pm before calling device_add in scsi_add_host_with_dmaHeiner Kallweit
Runtime PM should be configured already once we call device_add. See also the description in this mail thread https://lists.linuxfoundation.org/pipermail/linux-pm/2009-November/023198.html or the order of calls e.g. in usb_new_device. The changed order also helps to avoid scenarios where runtime pm for &shost->shost_gendev is activated whilst the parent is suspended, resulting in error message "runtime PM trying to activate child device hostx but parent yyy is not active". In addition properly reverse the runtime pm calls in the error path. Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> Acked-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2016-07-15scsi: remove the disable_blk_mq host flagChristoph Hellwig
We've had scsi-mq for 2.5 years now, so we can remove the unused flag to disable the code on a per-host basis that was put in for unexpected emergencies during bringup. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2016-03-18Merge branch 'for-4.6' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata Pull libata updates from Tejun Heo: - ahci grew runtime power management support so that the controller can be turned off if no devices are attached. - sata_via isn't dead yet. It got hotplug support and more refined workaround for certain WD drives. - Misc cleanups. There's a merge from for-4.5-fixes to avoid confusing conflicts in ahci PCI ID table. * 'for-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/libata: ata: ahci_xgene: dereferencing uninitialized pointer in probe AHCI: Remove obsolete Intel Lewisburg SATA RAID device IDs ata: sata_rcar: Use ARCH_RENESAS sata_via: Implement hotplug for VT6421 sata_via: Apply WD workaround only when needed on VT6421 ahci: Add runtime PM support for the host controller ahci: Add functions to manage runtime PM of AHCI ports ahci: Convert driver to use modern PM hooks ahci: Cache host controller version scsi: Drop runtime PM usage count after host is added scsi: Set request queue runtime PM status back to active on resume block: Add blk_set_runtime_active() ata: ahci_mvebu: add support for Armada 3700 variant libata: fix unbalanced spin_lock_irqsave/spin_unlock_irq() in ata_scsi_park_show() libata: support AHCI on OCTEON platform
2016-02-23scsi: Use ida for host number managementLee Duncan
Update the SCSI hosts module to use ida to manage its host_no index instead of an atomic integer. This means that the SCSI host number will now be reclaimable. Use the ida "simple" mechanism, since there should be no need for a separate spin lock current usage. Ida was chosen over idr because the hosts module already has its own instance and locking mechanisms that aren't easily changed. Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Lee Duncan <lduncan@suse.com> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2016-02-19scsi: Drop runtime PM usage count after host is addedMika Westerberg
Runtime PM of the SCSI host is already handled by calls to scsi_autopm_get_host() and scsi_autopm_put_host() from appropriate places whenever the host needs to be powered on. This works fine when there is device connected to the host as once it runtime suspends the host will too. However, if there is no device connected the host is never runtime suspended (the usage counter is always 0). Allow runtime suspend of host even if it has no devices connected by calling scsi_autopm_put_host() at the end of scsi_add_host_with_dma(). We temporarily increase runtime PM usage counter first so call to scsi_autopm_put_host() will result idle request to be scheduled for the device. Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2015-12-03Merge branch 'mkp-fixes' into fixesJames Bottomley
2015-11-30Fix a memory leak in scsi_host_dev_release()Bart Van Assche
Avoid that kmemleak reports the following memory leak if a SCSI LLD calls scsi_host_alloc() and scsi_host_put() but neither scsi_host_add() nor scsi_host_remove(). The following shell command triggers that scenario: for ((i=0; i<2; i++)); do srp_daemon -oac | while read line; do echo $line >/sys/class/infiniband_srp/srp-mlx4_0-1/add_target done done unreferenced object 0xffff88021b24a220 (size 8): comm "srp_daemon", pid 56421, jiffies 4295006762 (age 4240.750s) hex dump (first 8 bytes): 68 6f 73 74 35 38 00 a5 host58.. backtrace: [<ffffffff8151014a>] kmemleak_alloc+0x7a/0xc0 [<ffffffff81165c1e>] __kmalloc_track_caller+0xfe/0x160 [<ffffffff81260d2b>] kvasprintf+0x5b/0x90 [<ffffffff81260e2d>] kvasprintf_const+0x8d/0xb0 [<ffffffff81254b0c>] kobject_set_name_vargs+0x3c/0xa0 [<ffffffff81337e3c>] dev_set_name+0x3c/0x40 [<ffffffff81355757>] scsi_host_alloc+0x327/0x4b0 [<ffffffffa03edc8e>] srp_create_target+0x4e/0x8a0 [ib_srp] [<ffffffff8133778b>] dev_attr_store+0x1b/0x20 [<ffffffff811f27fa>] sysfs_kf_write+0x4a/0x60 [<ffffffff811f1e8e>] kernfs_fop_write+0x14e/0x180 [<ffffffff81176eef>] __vfs_write+0x2f/0xf0 [<ffffffff811771e4>] vfs_write+0xa4/0x100 [<ffffffff81177c64>] SyS_write+0x54/0xc0 [<ffffffff8151b257>] entry_SYSCALL_64_fastpath+0x12/0x6f Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> Reviewed-by: Lee Duncan <lduncan@suse.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Hannes Reinecke <hare@suse.de> Cc: stable <stable@vger.kernel.org> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
2015-11-09scsi: use host wide tags by defaultChristoph Hellwig
This patch changes the !blk-mq path to the same defaults as the blk-mq I/O path by always enabling block tagging, and always using host wide tags. We've had blk-mq available for a few releases so bugs with this mode should have been ironed out, and this ensures we get better coverage of over tagging setup over different configs. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Jens Axboe <axboe@kernel.dk> Reviewed-by: Hannes Reinecke <hare@suse.de> Signed-off-by: James Bottomley <JBottomley@Odin.com>
2014-11-12scsi: remove ordered_tag host template fieldChristoph Hellwig
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Mike Christie <michaelc@cs.wisc.edu> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.de>
2014-11-12scsi: fixup logging messages in scsi_error.cHannes Reinecke
Use the matching scope for logging messages to allow for better command tracing. Signed-off-by: Hannes Reinecke <hare@suse.de> Suggested-by: Robert Elliott <elliott@hp.com> Reviewed-by: Robert Elliott <elliott@hp.com> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-07-25scsi: add support for a blk-mq based I/O path.Christoph Hellwig
This patch adds support for an alternate I/O path in the scsi midlayer which uses the blk-mq infrastructure instead of the legacy request code. Use of blk-mq is fully transparent to drivers, although for now a host template field is provided to opt out of blk-mq usage in case any unforseen incompatibilities arise. In general replacing the legacy request code with blk-mq is a simple and mostly mechanical transformation. The biggest exception is the new code that deals with the fact the I/O submissions in blk-mq must happen from process context, which slightly complicates the I/O completion handler. The second biggest differences is that blk-mq is build around the concept of preallocated requests that also include driver specific data, which in SCSI context means the scsi_cmnd structure. This completely avoids dynamic memory allocations for the fast path through I/O submission. Due the preallocated requests the MQ code path exclusively uses the host-wide shared tag allocator instead of a per-LUN one. This only affects drivers actually using the block layer provided tag allocator instead of their own. Unlike the old path blk-mq always provides a tag, although drivers don't have to use it. For now the blk-mq path is disable by defauly and must be enabled using the "use_blk_mq" module parameter. Once the remaining work in the block layer to make blk-mq more suitable for slow devices is complete I hope to make it the default and eventually even remove the old code path. Based on the earlier scsi-mq prototype by Nicholas Bellinger. Thanks to Bart Van Assche and Robert Elliot for testing, benchmarking and various sugestions and code contributions. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Webb Scales <webbnh@hp.com> Acked-by: Jens Axboe <axboe@kernel.dk> Tested-by: Bart Van Assche <bvanassche@acm.org> Tested-by: Robert Elliott <elliott@hp.com>
2014-07-17scsi: use dev_printk variants where possibleHannes Reinecke
Using dev_printk variants prefixes the logging message with the originating device, which makes debugging easier. Signed-off-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christoph Hellwig <hch@lst.de>
2014-03-15[SCSI] scsi_error: disable eh_deadline if no host_reset_handler is setHannes Reinecke
When the host template doesn't declare an eh_host_reset_handler the eh_deadline mechanism is pointless and will set the device to offline. So disable eh_deadline if no eh_host_reset_handler is present. Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-12-19[SCSI] Set the minimum valid value of 'eh_deadline' as 0Ren Mingxin
The former minimum valid value of 'eh_deadline' is 1s, which means the earliest occasion to shorten EH is 1 second later since a command is failed or timed out. But if we want to skip EH steps ASAP, we have to wait until the first EH step is finished. If the duration of the first EH step is long, this waiting time is excruciating. So, it is necessary to accept 0 as the minimum valid value for 'eh_deadline'. According to my test, with Hannes' patchset 'New EH command timeout handler' as well, the minimum IO time is improved from 73s (eh_deadline = 1) to 43s(eh_deadline = 0) when commands are timed out by disabling RSCN and target port. Signed-off-by: Ren Mingxin <renmx@cn.fujitsu.com> Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-12-19[SCSI] improved eh timeout handlerHannes Reinecke
When a command runs into a timeout we need to send an 'ABORT TASK' TMF. This is typically done by the 'eh_abort_handler' LLDD callback. Conceptually, however, this function is a normal SCSI command, so there is no need to enter the error handler. This patch implements a new scsi_abort_command() function which invokes an asynchronous function scsi_eh_abort_handler() to abort the commands via the usual 'eh_abort_handler'. If abort succeeds the command is either retried or terminated, depending on the number of allowed retries. However, 'eh_eflags' records the abort, so if the retry would fail again the command is pushed onto the error handler without trying to abort it (again); it'll be cleared up from SCSI EH. [hare: smatch detected stray switch fixed] Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-11-29[SCSI] Disable WRITE SAME for RAID and virtual host adapter driversMartin K. Petersen
Some host adapters do not pass commands through to the target disk directly. Instead they provide an emulated target which may or may not accurately report its capabilities. In some cases the physical device characteristics are reported even when the host adapter is processing commands on the device's behalf. This can lead to adapter firmware hangs or excessive I/O errors. This patch disables WRITE SAME for devices connected to host adapters that provide an emulated target. Driver writers can disable WRITE SAME by setting the no_write_same flag in the host adapter template. [jejb: fix up rejections due to eh_deadline patch] Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Cc: stable@kernel.org Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-10-25[SCSI] Add 'eh_deadline' to limit SCSI EH runtimeHannes Reinecke
This patchs adds an 'eh_deadline' sysfs attribute to the scsi host which limits the overall runtime of the SCSI EH. The 'eh_deadline' value is stored in the now obsolete field 'resetting'. When a command is failed the start time of the EH is stored in 'last_reset'. If the overall runtime of the SCSI EH is longer than last_reset + eh_deadline, the EH is short-circuited and falls through to issue a host reset only. [jejb: add comments in Scsi_Host about new fields] Signed-off-by: Hannes Reinecke <hare@suse.de> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2013-02-06driver-core: constify data for class_find_device()Michał Mirosław
All in-kernel users of class_find_device() don't really need mutable data for match callback. In two places (kernel/power/suspend_test.c, drivers/scsi/osd/osd_uld.c) this patch changes match callbacks to use const search data. The const is propagated to rtc_class_open() and power_supply_get_by_name() parameters. Note that there's a dev reference leak in suspend_test.c that's not touched in this patch. Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl> Acked-by: Grant Likely <grant.likely@secretlab.ca> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-07-20[SCSI] Fix device removal NULL pointer dereferenceBart Van Assche
Use blk_queue_dead() to test whether the queue is dead instead of !sdev. Since scsi_prep_fn() may be invoked concurrently with __scsi_remove_device(), keep the queuedata (sdev) pointer in __scsi_remove_device(). This patch fixes a kernel oops that can be triggered by USB device removal. See also http://www.spinics.net/lists/linux-scsi/msg56254.html. Other changes included in this patch: - Swap the blk_cleanup_queue() and kfree() calls in scsi_host_dev_release() to make that code easier to grasp. - Remove the queue dead check from scsi_run_queue() since the queue state can change anyway at any point in that function where the queue lock is not held. - Remove the queue dead check from the start of scsi_request_fn() since it is redundant with the scsi_device_online() check. Reported-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Signed-off-by: Bart Van Assche <bvanassche@acm.org> Reviewed-by: Mike Christie <michaelc@cs.wisc.edu> Reviewed-by: Tejun Heo <tj@kernel.org> Cc: <stable@kernel.org> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-07-20[SCSI] properly initialize atomic_tJosh Hunt
Initialize atomic_t scsi_host_next_hn and ioerr_cntas per the guidelines defined in Documentation/atomic_ops.txt Signed-off-by: Josh Hunt <johunt@akamai.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2012-05-10[SCSI] fix oops in all legacy host adapters caused by 6f381faJames Bottomley
Commit 6f381fa344911d5a234b13574433cf23036f9467 Author: Lin Ming <ming.m.lin@intel.com> [SCSI] scsi_lib: use correct DMA device in __scsi_alloc_queue Caused a regression where we oops in every legacy mode SCSI host driver because they supply a NULL pointer to scsi_add_host(). Fix this by checking for the NULL in scsi_add_host_with_dma() and changing the DMA device to being the platform_bus in that case (which replicates the original behaviour). Reported-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2011-10-30[SCSI] Make scsi_free_queue() kill pending SCSI commandsBart Van Assche
Make sure that SCSI device removal via scsi_remove_host() does finish all pending SCSI commands. Currently that's not the case and hence removal of a SCSI host during I/O can cause a deadlock. See also "blkdev_issue_discard() hangs forever if underlying storage device is removed" (http://bugzilla.kernel.org/show_bug.cgi?id=40472). See also http://lkml.org/lkml/2011/8/27/6. Signed-off-by: Bart Van Assche <bvanassche@acm.org> Cc: <stable@kernel.org> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
2010-10-22Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6Linus Torvalds
* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6: (31 commits) driver core: Display error codes when class suspend fails Driver core: Add section count to memory_block struct Driver core: Add mutex for adding/removing memory blocks Driver core: Move find_memory_block routine hpilo: Despecificate driver from iLO generation driver core: Convert link_mem_sections to use find_memory_block_hinted. driver core: Introduce find_memory_block_hinted which utilizes kset_find_obj_hinted. kobject: Introduce kset_find_obj_hinted. driver core: fix build for CONFIG_BLOCK not enabled driver-core: base: change to new flag variable sysfs: only access bin file vm_ops with the active lock sysfs: Fail bin file mmap if vma close is implemented. FW_LOADER: fix kconfig dependency warning on HOTPLUG uio: Statically allocate uio_class and use class .dev_attrs. uio: Support 2^MINOR_BITS minors uio: Cleanup irq handling. uio: Don't clear driver data uio: Fix lack of locking in init_uio_class SYSFS: Allow boot time switching between deprecated and modern sysfs layout driver core: remove CONFIG_SYSFS_DEPRECATED_V2 but keep it for block devices ...
2010-10-22driver core: remove CONFIG_SYSFS_DEPRECATED_V2 but keep it for block devicesKay Sievers
This patch removes the old CONFIG_SYSFS_DEPRECATED_V2 config option, but it keeps the logic around to handle block devices in the old manner as some people like to run new kernel versions on old (pre 2007/2008) distros. Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Stephen Hemminger <shemminger@vyatta.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: "James E.J. Bottomley" <James.Bottomley@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Cc: Randy Dunlap <randy.dunlap@oracle.com> Cc: Tejun Heo <tj@kernel.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Jaroslav Kysela <perex@perex.cz> Cc: Takashi Iwai <tiwai@suse.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-09-10block/scsi: Provide a limit on the number of integrity segmentsMartin K. Petersen
Some controllers have a hardware limit on the number of protection information scatter-gather list segments they can handle. Introduce a max_integrity_segments limit in the block layer and provide a new scsi_host_template setting that allows HBA drivers to provide a value suitable for the hardware. Add support for honoring the integrity segment limit when merging both bios and requests. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: Jens Axboe <axboe@carl.home.kernel.dk>
2010-07-28[SCSI] implement runtime Power ManagementAlan Stern
This patch (as1398b) adds runtime PM support to the SCSI layer. Only the machanism is provided; use of it is up to the various high-level drivers, and the patch doesn't change any of them. Except for sg -- the patch expicitly prevents a device from being runtime-suspended while its sg device file is open. The implementation is simplistic. In general, hosts and targets are automatically suspended when all their children are asleep, but for them the runtime-suspend code doesn't actually do anything. (A host's runtime PM status is propagated up the device tree, though, so a runtime-PM-aware lower-level driver could power down the host adapter hardware at the appropriate times.) There are comments indicating where a transport class might be notified or some other hooks added. LUNs are runtime-suspended by calling the drivers' existing suspend handlers (and likewise for runtime-resume). Somewhat arbitrarily, the implementation delays for 100 ms before suspending an eligible LUN. This is because there typically are occasions during bootup when the same device file is opened and closed several times in quick succession. The way this all works is that the SCSI core increments a device's PM-usage count when it is registered. If a high-level driver does nothing then the device will not be eligible for runtime-suspend because of the elevated usage count. If a high-level driver wants to use runtime PM then it can call scsi_autopm_put_device() in its probe routine to decrement the usage count and scsi_autopm_get_device() in its remove routine to restore the original count. Hosts, targets, and LUNs are not suspended while they are being probed or removed, or while the error handler is running. In fact, a fairly large part of the patch consists of code to make sure that things aren't suspended at such times. [jejb: fix up compile issues in PM config variations] Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: James Bottomley <James.Bottomley@suse.de>