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> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
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@ -24,7 +24,6 @@
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#include <linux/pci.h>
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#include <linux/slab.h>
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#include <linux/uio_driver.h>
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#include <linux/spinlock.h>
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#define DRIVER_VERSION "0.01.0"
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#define DRIVER_AUTHOR "Michael S. Tsirkin <mst@redhat.com>"
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@ -33,7 +32,6 @@
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struct uio_pci_generic_dev {
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struct uio_info info;
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struct pci_dev *pdev;
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spinlock_t lock; /* guards command register accesses */
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};
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static inline struct uio_pci_generic_dev *
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@ -57,7 +55,6 @@ static irqreturn_t irqhandler(int irq, struct uio_info *info)
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BUILD_BUG_ON(PCI_COMMAND % 4);
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BUILD_BUG_ON(PCI_COMMAND + 2 != PCI_STATUS);
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spin_lock_irq(&gdev->lock);
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pci_block_user_cfg_access(pdev);
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/* Read both command and status registers in a single 32-bit operation.
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@ -83,7 +80,6 @@ static irqreturn_t irqhandler(int irq, struct uio_info *info)
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done:
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pci_unblock_user_cfg_access(pdev);
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spin_unlock_irq(&gdev->lock);
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return ret;
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}
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@ -158,7 +154,6 @@ static int __devinit probe(struct pci_dev *pdev,
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gdev->info.irq_flags = IRQF_SHARED;
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gdev->info.handler = irqhandler;
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gdev->pdev = pdev;
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spin_lock_init(&gdev->lock);
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if (uio_register_device(&pdev->dev, &gdev->info))
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goto err_register;
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