[PATCH 1/2] scsi: mpi3mr: delete unnecessary NULL check

[PATCH 1/2] scsi: mpi3mr: delete unnecessary NULL check

[Dan Carpenter]

The "mrioc->intr_info" pointer can't be NULL, but if it could then the
second iteration through the loop would Oops.  Let's delete the
confusing and impossible NULL check.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
 drivers/scsi/mpi3mr/mpi3mr_fw.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/scsi/mpi3mr/mpi3mr_fw.c b/drivers/scsi/mpi3mr/mpi3mr_fw.c
index acb2be62080a..40696b75345d 100644
--- a/drivers/scsi/mpi3mr/mpi3mr_fw.c
+++ b/drivers/scsi/mpi3mr/mpi3mr_fw.c
@@ -3583,8 +3583,7 @@ static void mpi3mr_free_mem(struct mpi3mr_ioc *mrioc)
 
 	for (i = 0; i < mrioc->intr_info_count; i++) {
 		intr_info = mrioc->intr_info + i;
-		if (intr_info)
-			intr_info->op_reply_q = NULL;
+		intr_info->op_reply_q = NULL;
 	}
 
 	kfree(mrioc->req_qinfo);
-- 
2.30.2

[PATCH 2/2] scsi: mpi3mr: Fix error handling in mpi3mr_setup_isr()

[Dan Carpenter]

The pci_alloc_irq_vectors_affinity() function returns negative error
codes or it returns a number between the minimum vectors (1 in this
case) and max_vectors.  It won't return zero.  Because "i" is a u16 then
the error handling won't work.  And also if it did work the error code
was not set.

Really "max_vectors" can be an int as well because we're doing a min_t()
on int type.  The other change is that it's better to remove unnecessary
initialization so that static checkers can warn us if there are ever
uninitialized variable bugs introduced in the future.

I changed the error code from -1 (-EPERM) if the kmalloc() failed to
-ENOMEM.  And on success path I changed it from "return retval;" to
"return 0;" which shouldn't affect the compiled code but makes it more
readable.

Fixes: 824a156633df ("scsi: mpi3mr: Base driver code")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
 drivers/scsi/mpi3mr/mpi3mr_fw.c | 24 +++++++++++++-----------
 1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/drivers/scsi/mpi3mr/mpi3mr_fw.c b/drivers/scsi/mpi3mr/mpi3mr_fw.c
index 40696b75345d..88db2f0e13fd 100644
--- a/drivers/scsi/mpi3mr/mpi3mr_fw.c
+++ b/drivers/scsi/mpi3mr/mpi3mr_fw.c
@@ -665,8 +665,9 @@ static inline int mpi3mr_request_irq(struct mpi3mr_ioc *mrioc, u16 index)
 static int mpi3mr_setup_isr(struct mpi3mr_ioc *mrioc, u8 setup_one)
 {
 	unsigned int irq_flags = PCI_IRQ_MSIX;
-	u16 max_vectors = 0, i;
-	int retval = 0;
+	int max_vectors;
+	int retval;
+	int i;
 	struct irq_affinity desc = { .pre_vectors =  1};
 
 	mpi3mr_cleanup_isr(mrioc);
@@ -687,29 +688,29 @@ static int mpi3mr_setup_isr(struct mpi3mr_ioc *mrioc, u8 setup_one)
 	irq_flags |= PCI_IRQ_AFFINITY | PCI_IRQ_ALL_TYPES;
 
 	mrioc->op_reply_q_offset = (max_vectors > 1) ? 1 : 0;
-	i = pci_alloc_irq_vectors_affinity(mrioc->pdev,
-	    1, max_vectors, irq_flags, &desc);
-	if (i <= 0) {
+	retval = pci_alloc_irq_vectors_affinity(mrioc->pdev,
+				1, max_vectors, irq_flags, &desc);
+	if (retval < 0) {
 		ioc_err(mrioc, "Cannot alloc irq vectors\n");
 		goto out_failed;
 	}
-	if (i != max_vectors) {
+	if (retval != max_vectors) {
 		ioc_info(mrioc,
 		    "allocated vectors (%d) are less than configured (%d)\n",
-		    i, max_vectors);
+		    retval, max_vectors);
 		/*
 		 * If only one MSI-x is allocated, then MSI-x 0 will be shared
 		 * between Admin queue and operational queue
 		 */
-		if (i == 1)
+		if (retval == 1)
 			mrioc->op_reply_q_offset = 0;
 
-		max_vectors = i;
+		max_vectors = retval;
 	}
 	mrioc->intr_info = kzalloc(sizeof(struct mpi3mr_intr_info) * max_vectors,
 	    GFP_KERNEL);
 	if (!mrioc->intr_info) {
-		retval = -1;
+		retval = -ENOMEM;
 		pci_free_irq_vectors(mrioc->pdev);
 		goto out_failed;
 	}
@@ -722,7 +723,8 @@ static int mpi3mr_setup_isr(struct mpi3mr_ioc *mrioc, u8 setup_one)
 	}
 	mrioc->intr_info_count = max_vectors;
 	mpi3mr_ioc_enable_intr(mrioc);
-	return retval;
+	return 0;
+
 out_failed:
 	mpi3mr_cleanup_isr(mrioc);
 
-- 
2.30.2

Re: [PATCH 1/2] scsi: mpi3mr: delete unnecessary NULL check

[Martin K. Petersen]

Dan,

> The "mrioc->intr_info" pointer can't be NULL, but if it could then the
> second iteration through the loop would Oops.  Let's delete the
> confusing and impossible NULL check.

Applied 1+2 to 5.14/scsi-staging, thanks!

-- 
Martin K. Petersen	Oracle Linux Engineering

Re: [PATCH 1/2] scsi: mpi3mr: delete unnecessary NULL check

[Martin K. Petersen]

On Wed, 9 Jun 2021 12:26:02 +0300, Dan Carpenter wrote:

> The "mrioc->intr_info" pointer can't be NULL, but if it could then the
> second iteration through the loop would Oops.  Let's delete the
> confusing and impossible NULL check.

Applied to 5.14/scsi-queue, thanks!

[1/2] scsi: mpi3mr: delete unnecessary NULL check
      https://git.kernel.org/mkp/scsi/c/d46bdecd9f3c
[2/2] scsi: mpi3mr: Fix error handling in mpi3mr_setup_isr()
      https://git.kernel.org/mkp/scsi/c/2938bedd0efa

-- 
Martin K. Petersen	Oracle Linux Engineering