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author | Nicholas Bellinger <nab@linux-iscsi.org> | 2016-01-11 21:31:09 -0800 |
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committer | Nicholas Bellinger <nab@linux-iscsi.org> | 2016-02-03 14:09:07 -0800 |
commit | febe562c20dfa8f33bee7d419c6b517986a5aa33 (patch) | |
tree | 8fab8d2713f877b4464739b302bda4b21c12436b /drivers/target/target_core_transport.c | |
parent | a07100e00ac42a4474530ce17b4978c9e06bde55 (diff) | |
download | op-kernel-dev-febe562c20dfa8f33bee7d419c6b517986a5aa33.zip op-kernel-dev-febe562c20dfa8f33bee7d419c6b517986a5aa33.tar.gz |
target: Fix LUN_RESET active I/O handling for ACK_KREF
This patch fixes a NULL pointer se_cmd->cmd_kref < 0
refcount bug during TMR LUN_RESET with active se_cmd
I/O, that can be triggered during se_cmd descriptor
shutdown + release via core_tmr_drain_state_list() code.
To address this bug, add common __target_check_io_state()
helper for ABORT_TASK + LUN_RESET w/ CMD_T_COMPLETE
checking, and set CMD_T_ABORTED + obtain ->cmd_kref for
both cases ahead of last target_put_sess_cmd() after
TFO->aborted_task() -> transport_cmd_finish_abort()
callback has completed.
It also introduces SCF_ACK_KREF to determine when
transport_cmd_finish_abort() needs to drop the second
extra reference, ahead of calling target_put_sess_cmd()
for the final kref_put(&se_cmd->cmd_kref).
It also updates transport_cmd_check_stop() to avoid
holding se_cmd->t_state_lock while dropping se_cmd
device state via target_remove_from_state_list(), now
that core_tmr_drain_state_list() is holding the
se_device lock while checking se_cmd state from
within TMR logic.
Finally, move transport_put_cmd() release of SGL +
TMR + extended CDB memory into target_free_cmd_mem()
in order to avoid potential resource leaks in TMR
ABORT_TASK + LUN_RESET code-paths. Also update
target_release_cmd_kref() accordingly.
Reviewed-by: Quinn Tran <quinn.tran@qlogic.com>
Cc: Himanshu Madhani <himanshu.madhani@qlogic.com>
Cc: Sagi Grimberg <sagig@mellanox.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Andy Grover <agrover@redhat.com>
Cc: Mike Christie <mchristi@redhat.com>
Cc: stable@vger.kernel.org # 3.10+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'drivers/target/target_core_transport.c')
-rw-r--r-- | drivers/target/target_core_transport.c | 67 |
1 files changed, 29 insertions, 38 deletions
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c index 9f3608e..af52f8b 100644 --- a/drivers/target/target_core_transport.c +++ b/drivers/target/target_core_transport.c @@ -534,9 +534,6 @@ void transport_deregister_session(struct se_session *se_sess) } EXPORT_SYMBOL(transport_deregister_session); -/* - * Called with cmd->t_state_lock held. - */ static void target_remove_from_state_list(struct se_cmd *cmd) { struct se_device *dev = cmd->se_dev; @@ -561,10 +558,6 @@ static int transport_cmd_check_stop(struct se_cmd *cmd, bool remove_from_lists, { unsigned long flags; - spin_lock_irqsave(&cmd->t_state_lock, flags); - if (write_pending) - cmd->t_state = TRANSPORT_WRITE_PENDING; - if (remove_from_lists) { target_remove_from_state_list(cmd); @@ -574,6 +567,10 @@ static int transport_cmd_check_stop(struct se_cmd *cmd, bool remove_from_lists, cmd->se_lun = NULL; } + spin_lock_irqsave(&cmd->t_state_lock, flags); + if (write_pending) + cmd->t_state = TRANSPORT_WRITE_PENDING; + /* * Determine if frontend context caller is requesting the stopping of * this command for frontend exceptions. @@ -627,6 +624,8 @@ static void transport_lun_remove_cmd(struct se_cmd *cmd) void transport_cmd_finish_abort(struct se_cmd *cmd, int remove) { + bool ack_kref = (cmd->se_cmd_flags & SCF_ACK_KREF); + if (cmd->se_cmd_flags & SCF_SE_LUN_CMD) transport_lun_remove_cmd(cmd); /* @@ -638,7 +637,7 @@ void transport_cmd_finish_abort(struct se_cmd *cmd, int remove) if (transport_cmd_check_stop_to_fabric(cmd)) return; - if (remove) + if (remove && ack_kref) transport_put_cmd(cmd); } @@ -706,7 +705,7 @@ void target_complete_cmd(struct se_cmd *cmd, u8 scsi_status) * Check for case where an explicit ABORT_TASK has been received * and transport_wait_for_tasks() will be waiting for completion.. */ - if (cmd->transport_state & CMD_T_ABORTED && + if (cmd->transport_state & CMD_T_ABORTED || cmd->transport_state & CMD_T_STOP) { spin_unlock_irqrestore(&cmd->t_state_lock, flags); complete_all(&cmd->t_transport_stop_comp); @@ -2222,20 +2221,14 @@ static inline void transport_free_pages(struct se_cmd *cmd) } /** - * transport_release_cmd - free a command - * @cmd: command to free + * transport_put_cmd - release a reference to a command + * @cmd: command to release * - * This routine unconditionally frees a command, and reference counting - * or list removal must be done in the caller. + * This routine releases our reference to the command and frees it if possible. */ -static int transport_release_cmd(struct se_cmd *cmd) +static int transport_put_cmd(struct se_cmd *cmd) { BUG_ON(!cmd->se_tfo); - - if (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB) - core_tmr_release_req(cmd->se_tmr_req); - if (cmd->t_task_cdb != cmd->__t_task_cdb) - kfree(cmd->t_task_cdb); /* * If this cmd has been setup with target_get_sess_cmd(), drop * the kref and call ->release_cmd() in kref callback. @@ -2243,18 +2236,6 @@ static int transport_release_cmd(struct se_cmd *cmd) return target_put_sess_cmd(cmd); } -/** - * transport_put_cmd - release a reference to a command - * @cmd: command to release - * - * This routine releases our reference to the command and frees it if possible. - */ -static int transport_put_cmd(struct se_cmd *cmd) -{ - transport_free_pages(cmd); - return transport_release_cmd(cmd); -} - void *transport_kmap_data_sg(struct se_cmd *cmd) { struct scatterlist *sg = cmd->t_data_sg; @@ -2452,14 +2433,13 @@ static void transport_write_pending_qf(struct se_cmd *cmd) int transport_generic_free_cmd(struct se_cmd *cmd, int wait_for_tasks) { - unsigned long flags; int ret = 0; if (!(cmd->se_cmd_flags & SCF_SE_LUN_CMD)) { if (wait_for_tasks && (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB)) - transport_wait_for_tasks(cmd); + transport_wait_for_tasks(cmd); - ret = transport_release_cmd(cmd); + ret = transport_put_cmd(cmd); } else { if (wait_for_tasks) transport_wait_for_tasks(cmd); @@ -2468,11 +2448,8 @@ int transport_generic_free_cmd(struct se_cmd *cmd, int wait_for_tasks) * has already added se_cmd to state_list, but fabric has * failed command before I/O submission. */ - if (cmd->state_active) { - spin_lock_irqsave(&cmd->t_state_lock, flags); + if (cmd->state_active) target_remove_from_state_list(cmd); - spin_unlock_irqrestore(&cmd->t_state_lock, flags); - } if (cmd->se_lun) transport_lun_remove_cmd(cmd); @@ -2517,6 +2494,16 @@ out: } EXPORT_SYMBOL(target_get_sess_cmd); +static void target_free_cmd_mem(struct se_cmd *cmd) +{ + transport_free_pages(cmd); + + if (cmd->se_cmd_flags & SCF_SCSI_TMR_CDB) + core_tmr_release_req(cmd->se_tmr_req); + if (cmd->t_task_cdb != cmd->__t_task_cdb) + kfree(cmd->t_task_cdb); +} + static void target_release_cmd_kref(struct kref *kref) { struct se_cmd *se_cmd = container_of(kref, struct se_cmd, cmd_kref); @@ -2526,17 +2513,20 @@ static void target_release_cmd_kref(struct kref *kref) spin_lock_irqsave(&se_sess->sess_cmd_lock, flags); if (list_empty(&se_cmd->se_cmd_list)) { spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags); + target_free_cmd_mem(se_cmd); se_cmd->se_tfo->release_cmd(se_cmd); return; } if (se_sess->sess_tearing_down && se_cmd->cmd_wait_set) { spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags); + target_free_cmd_mem(se_cmd); complete(&se_cmd->cmd_wait_comp); return; } list_del(&se_cmd->se_cmd_list); spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags); + target_free_cmd_mem(se_cmd); se_cmd->se_tfo->release_cmd(se_cmd); } @@ -2548,6 +2538,7 @@ int target_put_sess_cmd(struct se_cmd *se_cmd) struct se_session *se_sess = se_cmd->se_sess; if (!se_sess) { + target_free_cmd_mem(se_cmd); se_cmd->se_tfo->release_cmd(se_cmd); return 1; } |