2023-12-20 23:11:16

by Jim Harris

Subject: [PATCH 1/2] Revert "PCI/IOV: Serialize sysfs sriov_numvfs reads vs writes"

The proper way to detect a change to the num_VFs value is to listen for a
sysfs event, not to add a device_lock() on the attribute _show() in the
kernel.

This reverts commit 35ff867b76576e32f34c698ccd11343f7d616204.
Revert had a small conflict, the sprintf() is now changed to sysfs_emit().

Suggested-by: Leon Romanovsky <[email protected]>
Signed-off-by: Jim Harris <[email protected]>
---
drivers/pci/iov.c | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index 25dbe85c4217..d4646bdcd887 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -395,14 +395,8 @@ static ssize_t sriov_numvfs_show(struct device *dev,
char *buf)
{
struct pci_dev *pdev = to_pci_dev(dev);
- u16 num_vfs;
-
- /* Serialize vs sriov_numvfs_store() so readers see valid num_VFs */
- device_lock(&pdev->dev);
- num_vfs = pdev->sriov->num_VFs;
- device_unlock(&pdev->dev);

- return sysfs_emit(buf, "%u\n", num_vfs);
+ return sysfs_emit(buf, "%u\n", pdev->sriov->num_VFs);
}

/*

2023-12-25 11:20:46

by Leon Romanovsky

Subject: Re: [PATCH 1/2] Revert "PCI/IOV: Serialize sysfs sriov_numvfs reads vs writes"

On Wed, Dec 20, 2023 at 10:58:17PM +0000, Jim Harris wrote:
> The proper way to detect a change to the num_VFs value is to listen for a
> sysfs event, not to add a device_lock() on the attribute _show() in the
> kernel.
>
> This reverts commit 35ff867b76576e32f34c698ccd11343f7d616204.
> Revert had a small conflict, the sprintf() is now changed to sysfs_emit().
>
> Suggested-by: Leon Romanovsky <[email protected]>
> Signed-off-by: Jim Harris <[email protected]>
> ---
> drivers/pci/iov.c | 8 +-------
> 1 file changed, 1 insertion(+), 7 deletions(-)
>

Thanks,
Reviewed-by: Leon Romanovsky <[email protected]>