linux/drivers/target
Mike Christie af1dd7ff46 tcmu: don't block submitting context for block waits
This patch has tcmu internally queue cmds if its ring buffer
is full. It also makes the TCMU_GLOBAL_MAX_BLOCKS limit a
hint instead of a hard limit, so we do not have to add any
new locks/atomics in the main IO path except when IO is not
running.

This fixes the following bugs:

1. We cannot sleep from the submitting context because it might be
called from a target recv context. This results in transport level
commands timing out. For example if the ring is full, we would
sleep, and a iscsi initiator would send a iscsi ping/nop which
times out because the target's recv thread is sleeping here.

2. Devices were not fairly scheduled to run when they hit the global
limit so they could time out waiting for ring space while others
got run.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2018-01-12 15:07:19 -08:00
..
iscsi Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2017-11-24 19:19:20 -10:00
loopback License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
sbp License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
tcm_fc License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
Kconfig block: make scsi_request and scsi ioctl support optional 2017-01-31 10:53:05 -07:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
target_core_alua.c target: fix ALUA state file path truncation 2017-11-04 15:00:30 -07:00
target_core_alua.h Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2017-11-24 19:19:20 -10:00
target_core_configfs.c Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2017-11-24 19:19:20 -10:00
target_core_device.c target: Fix cmd size for PR-OUT in passthrough_parse_cdb 2017-07-09 20:58:49 -07:00
target_core_fabric_configfs.c target: Move a declaration of a global variable into a header file 2017-11-04 15:15:30 -07:00
target_core_fabric_lib.c target-core: don't use "const char*" for a buffer that is written to 2018-01-12 15:07:09 -08:00
target_core_file.c target/file: Do not return error for UNMAP if length is zero 2017-11-04 14:45:16 -07:00
target_core_file.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
target_core_hba.c target: Fix target_sense_desc_format NULL pointer dereference 2015-09-24 23:17:23 -07:00
target_core_iblock.c block: replace bi_bdev with a gendisk pointer and partitions index 2017-08-23 12:49:55 -06:00
target_core_iblock.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
target_core_internal.h target-core: don't use "const char*" for a buffer that is written to 2018-01-12 15:07:09 -08:00
target_core_pr.c target-core: don't use "const char*" for a buffer that is written to 2018-01-12 15:07:09 -08:00
target_core_pr.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
target_core_pscsi.c block: fix blk_rq_append_bio 2017-12-18 13:55:43 -07:00
target_core_pscsi.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
target_core_rd.c target: break up free_device callback 2017-07-06 23:11:37 -07:00
target_core_rd.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
target_core_sbc.c Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2017-07-13 14:27:32 -07:00
target_core_spc.c target: Fix cmd size for PR-OUT in passthrough_parse_cdb 2017-07-09 20:58:49 -07:00
target_core_stat.c target: make config_item_type const 2017-10-19 16:15:17 +02:00
target_core_tmr.c target: Avoid early CMD_T_PRE_EXECUTE failures during ABORT_TASK 2017-11-07 19:50:24 -08:00
target_core_tpg.c target: Fix node_acl demo-mode + uncached dynamic shutdown regression 2017-08-09 20:55:19 -07:00
target_core_transport.c target: Avoid early CMD_T_PRE_EXECUTE failures during ABORT_TASK 2017-11-07 19:50:24 -08:00
target_core_ua.c Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending 2015-07-04 14:13:43 -07:00
target_core_ua.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
target_core_user.c tcmu: don't block submitting context for block waits 2018-01-12 15:07:19 -08:00
target_core_xcopy.c xcopy: loop over devices using idr helper 2017-07-06 23:11:40 -07:00
target_core_xcopy.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00