diff mbox series

[3/5] scsi: lpfc: fix lpfc_cpu_affinity_check() if no further cpus set

Message ID 20230306160651.2016767-4-vernon2gm@gmail.com
State New
Headers show
Series fix call cpumask_next() if no further cpus set | expand

Commit Message

Vernon Yang March 6, 2023, 4:06 p.m. UTC 
After commit 596ff4a09b89 ("cpumask: re-introduce constant-sized cpumask
optimizations"), when NR_CPUS <= BITS_PER_LONG, small_cpumask_bits used
a macro instead of variable-sized for efficient.

If no further cpus set, the cpumask_next() returns small_cpumask_bits,
it must greater than or equal to nr_cpumask_bits, so fix it to correctly.

Signed-off-by: Vernon Yang <vernon2gm@gmail.com>
---
 drivers/scsi/lpfc/lpfc_init.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

Comments

Vernon Yang March 6, 2023, 8:09 p.m. UTC | #1 
On Mon, Mar 06, 2023 at 10:48:04AM -0800, Linus Torvalds wrote:
> On Mon, Mar 6, 2023 at 8:07 AM Vernon Yang <vernon2gm@gmail.com> wrote:
> >
> > -                               if (new_cpu == nr_cpumask_bits)
> > +                               if (new_cpu >= nr_cpumask_bits)
>
> This all should use "nr_cpu_ids", not "nr_cpumask_bits".
>
> But I really suspect that it should all be rewritten to not do that
> thing over and over, but just use a helper function for it.
>
>   int lpfc_next_present_cpu(int n, int alternate)
>   {
>         n = cpumask_next(n, cpu_present_mask);
>         if (n >= nr_cpu_ids)
>                 n = alternate;
>         return n;
>   }
>
> and then you could just use
>
>         start_cpu = lpfc_next_present_cpu(new_cpu, first_cpu);

OK, thanks you very much.

I'll send a second version shortly

>
> or similar.
>
>               Linus
>
> PS. We "kind of" already have a helper function for this:
> cpumask_next_wrap(). But it's really meant for a different pattern
> entirely, so let's not confuse things.
diff mbox series

Patch

diff --git a/drivers/scsi/lpfc/lpfc_init.c b/drivers/scsi/lpfc/lpfc_init.c
index 61958a24a43d..01c0e2f47cf7 100644
--- a/drivers/scsi/lpfc/lpfc_init.c
+++ b/drivers/scsi/lpfc/lpfc_init.c
@@ -12563,7 +12563,7 @@  lpfc_cpu_affinity_check(struct lpfc_hba *phba, int vectors)
 					goto found_same;
 				new_cpu = cpumask_next(
 					new_cpu, cpu_present_mask);
-				if (new_cpu == nr_cpumask_bits)
+				if (new_cpu >= nr_cpumask_bits)
 					new_cpu = first_cpu;
 			}
 			/* At this point, we leave the CPU as unassigned */
@@ -12577,7 +12577,7 @@  lpfc_cpu_affinity_check(struct lpfc_hba *phba, int vectors)
 			 * selecting the same IRQ.
 			 */
 			start_cpu = cpumask_next(new_cpu, cpu_present_mask);
-			if (start_cpu == nr_cpumask_bits)
+			if (start_cpu >= nr_cpumask_bits)
 				start_cpu = first_cpu;
 
 			lpfc_printf_log(phba, KERN_INFO, LOG_INIT,
@@ -12613,7 +12613,7 @@  lpfc_cpu_affinity_check(struct lpfc_hba *phba, int vectors)
 					goto found_any;
 				new_cpu = cpumask_next(
 					new_cpu, cpu_present_mask);
-				if (new_cpu == nr_cpumask_bits)
+				if (new_cpu >= nr_cpumask_bits)
 					new_cpu = first_cpu;
 			}
 			/* We should never leave an entry unassigned */
@@ -12631,7 +12631,7 @@  lpfc_cpu_affinity_check(struct lpfc_hba *phba, int vectors)
 			 * selecting the same IRQ.
 			 */
 			start_cpu = cpumask_next(new_cpu, cpu_present_mask);
-			if (start_cpu == nr_cpumask_bits)
+			if (start_cpu >= nr_cpumask_bits)
 				start_cpu = first_cpu;
 
 			lpfc_printf_log(phba, KERN_INFO, LOG_INIT,
@@ -12704,7 +12704,7 @@  lpfc_cpu_affinity_check(struct lpfc_hba *phba, int vectors)
 				goto found_hdwq;
 			}
 			new_cpu = cpumask_next(new_cpu, cpu_present_mask);
-			if (new_cpu == nr_cpumask_bits)
+			if (new_cpu >= nr_cpumask_bits)
 				new_cpu = first_cpu;
 		}
 
@@ -12719,7 +12719,7 @@  lpfc_cpu_affinity_check(struct lpfc_hba *phba, int vectors)
 				goto found_hdwq;
 
 			new_cpu = cpumask_next(new_cpu, cpu_present_mask);
-			if (new_cpu == nr_cpumask_bits)
+			if (new_cpu >= nr_cpumask_bits)
 				new_cpu = first_cpu;
 		}
 
@@ -12730,7 +12730,7 @@  lpfc_cpu_affinity_check(struct lpfc_hba *phba, int vectors)
  found_hdwq:
 		/* We found an available entry, copy the IRQ info */
 		start_cpu = cpumask_next(new_cpu, cpu_present_mask);
-		if (start_cpu == nr_cpumask_bits)
+		if (start_cpu >= nr_cpumask_bits)
 			start_cpu = first_cpu;
 		cpup->hdwq = new_cpup->hdwq;
  logit: