| Message ID | 20230406101819.10109-1-ranjan.kumar@broadcom.com |
|---|---|
| State | New |
| Headers | show |
| Series | mpi3mr: IRQ save variants of spinlock to protect chain frame allocation | expand |
Ranjan, > Driver use spin lock without irqsave when it needs to acquire a chain > frame to protect chain frame allocation from multiple submission > threads. If there is any I/O queued from an interrupt context and if > that requires a chain frame and if the chain lock is held by the CPU > which got interrupted then there will be a possible deadlock. Applied to 6.4/scsi-staging, thanks!
diff --git a/drivers/scsi/mpi3mr/mpi3mr_os.c b/drivers/scsi/mpi3mr/mpi3mr_os.c index 6d55698ea4d1..ee6af3d4d667 100644 --- a/drivers/scsi/mpi3mr/mpi3mr_os.c +++ b/drivers/scsi/mpi3mr/mpi3mr_os.c @@ -3311,19 +3311,19 @@ static int mpi3mr_get_chain_idx(struct mpi3mr_ioc *mrioc) { u8 retry_count = 5; int cmd_idx = -1; + unsigned long flags; + spin_lock_irqsave(&mrioc->chain_buf_lock, flags); do { - spin_lock(&mrioc->chain_buf_lock); cmd_idx = find_first_zero_bit(mrioc->chain_bitmap, mrioc->chain_buf_count); if (cmd_idx < mrioc->chain_buf_count) { set_bit(cmd_idx, mrioc->chain_bitmap); - spin_unlock(&mrioc->chain_buf_lock); break; } - spin_unlock(&mrioc->chain_buf_lock); cmd_idx = -1; } while (retry_count--); + spin_unlock_irqrestore(&mrioc->chain_buf_lock, flags); return cmd_idx; }
Driver use spin lock without irqsave when it needs to acquire a chain frame to protect chain frame allocation from multiple submission threads. If there is any I/O queued from an interrupt context and if that requires a chain frame and if the chain lock is held by the CPU which got interrupted then there will be a possible deadlock. Signed-off-by: Ranjan Kumar <ranjan.kumar@broadcom.com> --- drivers/scsi/mpi3mr/mpi3mr_os.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)