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floppy: use atomic type for usage_count
The usage_count was being protected by a lock which was only there to create an atomic counter. Signed-off-by: Stephen Hemminger <shemminger@vyatta.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
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41a55b4de3
commit
575cfc673e
@ -578,7 +578,7 @@ static void reset_fdc(void);
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#define NEED_1_RECAL -2
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#define NEED_2_RECAL -3
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static int usage_count;
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static atomic_t usage_count = ATOMIC_INIT(0);
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/* buffer related variables */
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static int buffer_track = -1;
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@ -860,7 +860,7 @@ static void set_fdc(int drive)
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/* locks the driver */
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static int _lock_fdc(int drive, bool interruptible, int line)
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{
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if (!usage_count) {
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if (atomic_read(&usage_count) == 0) {
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pr_err("Trying to lock fdc while usage count=0 at line %d\n",
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line);
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return -1;
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@ -2941,7 +2941,7 @@ static void do_fd_request(struct request_queue *q)
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return;
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}
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if (usage_count == 0) {
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if (atomic_read(&usage_count) == 0) {
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pr_info("warning: usage count=0, current_req=%p exiting\n",
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current_req);
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pr_info("sect=%ld type=%x flags=%x\n",
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@ -3858,7 +3858,7 @@ static int floppy_revalidate(struct gendisk *disk)
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if (test_bit(FD_DISK_CHANGED_BIT, &UDRS->flags) ||
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test_bit(FD_VERIFY_BIT, &UDRS->flags) ||
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test_bit(drive, &fake_change) || NO_GEOM) {
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if (usage_count == 0) {
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if (atomic_read(&usage_count) == 0) {
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pr_info("VFS: revalidate called on non-open device.\n");
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return -EFAULT;
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}
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@ -4357,7 +4357,7 @@ out_unreg_platform_dev:
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platform_device_unregister(&floppy_device[drive]);
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out_flush_work:
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flush_scheduled_work();
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if (usage_count)
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if (atomic_read(&usage_count))
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floppy_release_irq_and_dma();
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out_unreg_region:
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blk_unregister_region(MKDEV(FLOPPY_MAJOR, 0), 256);
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@ -4374,8 +4374,6 @@ out_put_disk:
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return err;
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}
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static DEFINE_SPINLOCK(floppy_usage_lock);
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static const struct io_region {
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int offset;
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int size;
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@ -4421,14 +4419,8 @@ static void floppy_release_regions(int fdc)
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static int floppy_grab_irq_and_dma(void)
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{
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unsigned long flags;
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spin_lock_irqsave(&floppy_usage_lock, flags);
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if (usage_count++) {
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spin_unlock_irqrestore(&floppy_usage_lock, flags);
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if (atomic_inc_return(&usage_count) > 1)
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return 0;
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}
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spin_unlock_irqrestore(&floppy_usage_lock, flags);
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/*
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* We might have scheduled a free_irq(), wait it to
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@ -4439,9 +4431,7 @@ static int floppy_grab_irq_and_dma(void)
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if (fd_request_irq()) {
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DPRINT("Unable to grab IRQ%d for the floppy driver\n",
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FLOPPY_IRQ);
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spin_lock_irqsave(&floppy_usage_lock, flags);
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usage_count--;
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spin_unlock_irqrestore(&floppy_usage_lock, flags);
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atomic_dec(&usage_count);
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return -1;
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}
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if (fd_request_dma()) {
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@ -4451,9 +4441,7 @@ static int floppy_grab_irq_and_dma(void)
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use_virtual_dma = can_use_virtual_dma = 1;
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if (!(can_use_virtual_dma & 1)) {
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fd_free_irq();
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spin_lock_irqsave(&floppy_usage_lock, flags);
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usage_count--;
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spin_unlock_irqrestore(&floppy_usage_lock, flags);
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atomic_dec(&usage_count);
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return -1;
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}
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}
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@ -4488,9 +4476,7 @@ cleanup:
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fd_free_dma();
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while (--fdc >= 0)
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floppy_release_regions(fdc);
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spin_lock_irqsave(&floppy_usage_lock, flags);
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usage_count--;
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spin_unlock_irqrestore(&floppy_usage_lock, flags);
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atomic_dec(&usage_count);
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return -1;
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}
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@ -4502,14 +4488,10 @@ static void floppy_release_irq_and_dma(void)
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#endif
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long tmpsize;
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unsigned long tmpaddr;
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unsigned long flags;
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spin_lock_irqsave(&floppy_usage_lock, flags);
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if (--usage_count) {
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spin_unlock_irqrestore(&floppy_usage_lock, flags);
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if (!atomic_dec_and_test(&usage_count))
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return;
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}
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spin_unlock_irqrestore(&floppy_usage_lock, flags);
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if (irqdma_allocated) {
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fd_disable_dma();
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fd_free_dma();
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@ -4602,7 +4584,7 @@ static void __exit floppy_module_exit(void)
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del_timer_sync(&fd_timer);
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blk_cleanup_queue(floppy_queue);
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if (usage_count)
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if (atomic_read(&usage_count))
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floppy_release_irq_and_dma();
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/* eject disk, if any */
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