Messages in this thread Patch in this message | | | Date | Tue, 9 Aug 2011 20:53:41 +0200 | From | "Hans J. Koch" <> | Subject | Re: [PATCH] uio/gen-pci: don't enable interrupts in ISR |
| |
On Tue, Aug 09, 2011 at 02:37:43PM +0300, Michael S. Tsirkin wrote: > > > > Should I hack up a patch to remove the lock, or do you have anything in your > > pipeline? > > > Please do. >
Here it is:
Greg (and anyone else...), you can also pull this from branch "uio-for-greg" from
git://hansjkoch.de/git/linux-hjk
From ff74627ade002d40fe1f902b7aadab8b1f15f889 Mon Sep 17 00:00:00 2001 From: "Hans J. Koch" <hjk@hansjkoch.de> Date: Tue, 9 Aug 2011 20:34:31 +0200 Subject: [PATCH] uio: uio_pci_generic: Remove useless spin_lock
The spin_lock in uio_pci_generic.c is only used in the interrupt handler, which cannot be executed twice at the same time. That makes the lock rather pointless. This patch removes it.
Cc: "Michael S. Tsirkin" <mst@redhat.com> Cc: Chris Wright <chrisw@redhat.com> Cc: Jesse Barnes <jbarnes@virtuousgeek.org> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Anthony Foiani <anthony.foiani@gmail.com> Reported-by: Anthony Foiani <anthony.foiani@gmail.com> Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Hans J. Koch <hjk@hansjkoch.de> --- drivers/uio/uio_pci_generic.c | 5 ----- 1 files changed, 0 insertions(+), 5 deletions(-)
diff --git a/drivers/uio/uio_pci_generic.c b/drivers/uio/uio_pci_generic.c index fc22e1e..02bd47b 100644 --- a/drivers/uio/uio_pci_generic.c +++ b/drivers/uio/uio_pci_generic.c @@ -24,7 +24,6 @@ #include <linux/pci.h> #include <linux/slab.h> #include <linux/uio_driver.h> -#include <linux/spinlock.h> #define DRIVER_VERSION "0.01.0" #define DRIVER_AUTHOR "Michael S. Tsirkin <mst@redhat.com>" @@ -33,7 +32,6 @@ struct uio_pci_generic_dev { struct uio_info info; struct pci_dev *pdev; - spinlock_t lock; /* guards command register accesses */ }; static inline struct uio_pci_generic_dev * @@ -57,7 +55,6 @@ static irqreturn_t irqhandler(int irq, struct uio_info *info) BUILD_BUG_ON(PCI_COMMAND % 4); BUILD_BUG_ON(PCI_COMMAND + 2 != PCI_STATUS); - spin_lock_irq(&gdev->lock); pci_block_user_cfg_access(pdev); /* Read both command and status registers in a single 32-bit operation. @@ -83,7 +80,6 @@ static irqreturn_t irqhandler(int irq, struct uio_info *info) done: pci_unblock_user_cfg_access(pdev); - spin_unlock_irq(&gdev->lock); return ret; } @@ -158,7 +154,6 @@ static int __devinit probe(struct pci_dev *pdev, gdev->info.irq_flags = IRQF_SHARED; gdev->info.handler = irqhandler; gdev->pdev = pdev; - spin_lock_init(&gdev->lock); if (uio_register_device(&pdev->dev, &gdev->info)) goto err_register; -- 1.7.5.4
| |