From: Raghava Aditya Renukunta <[email protected]> The driver utilizes an array of atomic variables to keep track of IO submissions to each vector. To submit an IO multiple threads iterate through the array to find a vector which has empty slots to send an IO. The reading and updating of the variable is not atomic, causing race conditions when a thread uses a full vector to submit an IO.
Fixed by mapping each FIB to a vector, the submission path then uses said vector to submit IO thereby removing the possibly of a race condition.The vector assignment is started from 1 since vector 0 is reserved for the use of AIF management FIBS.If the number of MSIx vectors is 1 (MSI or INTx mode) then all the fibs are allocated to vector 0. Signed-off-by: Raghava Aditya Renukunta <[email protected]> --- drivers/scsi/aacraid/aacraid.h | 1 + drivers/scsi/aacraid/commsup.c | 12 ++++++++++++ drivers/scsi/aacraid/src.c | 30 +++++++----------------------- 3 files changed, 20 insertions(+), 23 deletions(-) diff --git a/drivers/scsi/aacraid/aacraid.h b/drivers/scsi/aacraid/aacraid.h index da227e8..d133c4a 100644 --- a/drivers/scsi/aacraid/aacraid.h +++ b/drivers/scsi/aacraid/aacraid.h @@ -944,6 +944,7 @@ struct fib { */ struct list_head fiblink; void *data; + u32 vector_no; struct hw_fib *hw_fib_va; /* Actual shared object */ dma_addr_t hw_fib_pa; /* physical address of hw_fib*/ }; diff --git a/drivers/scsi/aacraid/commsup.c b/drivers/scsi/aacraid/commsup.c index b5b653c..b257d3b 100644 --- a/drivers/scsi/aacraid/commsup.c +++ b/drivers/scsi/aacraid/commsup.c @@ -104,6 +104,7 @@ int aac_fib_setup(struct aac_dev * dev) struct hw_fib *hw_fib; dma_addr_t hw_fib_pa; int i; + u32 vector = 1; while (((i = fib_map_alloc(dev)) == -ENOMEM) && (dev->scsi_host_ptr->can_queue > (64 - AAC_NUM_MGT_FIB))) { @@ -150,6 +151,17 @@ int aac_fib_setup(struct aac_dev * dev) dev->max_fib_size + sizeof(struct aac_fib_xporthdr)); hw_fib_pa = hw_fib_pa + dev->max_fib_size + sizeof(struct aac_fib_xporthdr); + + if ((dev->max_msix == 1) || + (i > ((dev->scsi_host_ptr->can_queue + AAC_NUM_MGT_FIB - 1) + - dev->vector_cap))) { + fibptr->vector_no = 0; + } else { + fibptr->vector_no = vector; + vector++; + if (vector == dev->max_msix) + vector = 1; + } } /* * Add the fib chain to the free list diff --git a/drivers/scsi/aacraid/src.c b/drivers/scsi/aacraid/src.c index 2aa34ea..bc0203f 100644 --- a/drivers/scsi/aacraid/src.c +++ b/drivers/scsi/aacraid/src.c @@ -156,8 +156,8 @@ static irqreturn_t aac_src_intr_message(int irq, void *dev_id) break; if (dev->msi_enabled && dev->max_msix > 1) atomic_dec(&dev->rrq_outstanding[vector_no]); - aac_intr_normal(dev, handle-1, 0, isFastResponse, NULL); dev->host_rrq[index++] = 0; + aac_intr_normal(dev, handle-1, 0, isFastResponse, NULL); if (index == (vector_no + 1) * dev->vector_cap) index = vector_no * dev->vector_cap; dev->host_rrq_idx[vector_no] = index; @@ -452,36 +452,20 @@ static int aac_src_deliver_message(struct fib *fib) #endif u16 hdr_size = le16_to_cpu(fib->hw_fib_va->header.Size); + u16 vector_no; atomic_inc(&q->numpending); if (dev->msi_enabled && fib->hw_fib_va->header.Command != AifRequest && dev->max_msix > 1) { - u_int16_t vector_no, first_choice = 0xffff; - - vector_no = dev->fibs_pushed_no % dev->max_msix; - do { - vector_no += 1; - if (vector_no == dev->max_msix) - vector_no = 1; - if (atomic_read(&dev->rrq_outstanding[vector_no]) < - dev->vector_cap) - break; - if (0xffff == first_choice) - first_choice = vector_no; - else if (vector_no == first_choice) - break; - } while (1); - if (vector_no == first_choice) - vector_no = 0; - atomic_inc(&dev->rrq_outstanding[vector_no]); - if (dev->fibs_pushed_no == 0xffffffff) - dev->fibs_pushed_no = 0; - else - dev->fibs_pushed_no++; + vector_no = fib->vector_no; fib->hw_fib_va->header.Handle += (vector_no << 16); + } else { + vector_no = 0; } + atomic_inc(&dev->rrq_outstanding[vector_no]); + if (dev->comm_interface == AAC_COMM_MESSAGE_TYPE2) { /* Calculate the amount to the fibsize bits */ fibsize = (hdr_size + 127) / 128 - 1; -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
