mpt2sas: Added driver module parameter max_msix_vectors

Added driver module parameter max_msix_vectors. Using this
module parameter the maximum number of MSI-X vectors could be set.

The number of MSI-X vectors used would be the minimum of MSI-X vectors
supported by the HBA, the number of CPU cores and the value set to
max_msix_vectors module parameters.

Signed-off-by: Sreekanth Reddy <Sreekanth.Reddy@avagotech.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

1 files changed, 14 insertions, 0 deletions

diff --git a/drivers/scsi/mpt2sas/mpt2sas_base.c b/drivers/scsi/mpt2sas/mpt2sas_base.c
index cf51b48dd7d9..b1726280595a 100644
--- a/drivers/scsi/mpt2sas/mpt2sas_base.c
+++ b/drivers/scsi/mpt2sas/mpt2sas_base.c
@@ -80,6 +80,10 @@ static int msix_disable = -1;
 module_param(msix_disable, int, 0);
 MODULE_PARM_DESC(msix_disable, " disable msix routed interrupts (default=0)");
 
+static int max_msix_vectors = -1;
+module_param(max_msix_vectors, int, 0);
+MODULE_PARM_DESC(max_msix_vectors, " max msix vectors ");
+
 static int mpt2sas_fwfault_debug;
 MODULE_PARM_DESC(mpt2sas_fwfault_debug, " enable detection of firmware fault "
         "and halt firmware - (default=0)");
@@ -1402,6 +1406,16 @@ _base_enable_msix(struct MPT2SAS_ADAPTER *ioc)
         ioc->reply_queue_count = min_t(int, ioc->cpu_count,
             ioc->msix_vector_count);
 
+        if (max_msix_vectors > 0) {
+                ioc->reply_queue_count = min_t(int, max_msix_vectors,
+                    ioc->reply_queue_count);
+                ioc->msix_vector_count = ioc->reply_queue_count;
+        }
+
+        printk(MPT2SAS_INFO_FMT
+        "MSI-X vectors supported: %d, no of cores: %d, max_msix_vectors: %d\n",
+         ioc->name, ioc->msix_vector_count, ioc->cpu_count, max_msix_vectors);
+
         entries = kcalloc(ioc->reply_queue_count, sizeof(struct msix_entry),
             GFP_KERNEL);
         if (!entries) {