[PATCH] libata: implement ata_poll_qc_complete and use it in polling functions (40e8c82c) · Commits · 戴 / test

[PATCH libata-dev-2.6:upstream] implement ata_poll_qc_complete and use it in polling functions Previously, libata polling functions turned irq back on and completed qc commands without holding host lock. This creates a race condition between the polling task and interrupts from other ports on the same host set or spurious interrupt from itself. This patch implements ata_poll_qc_complete which enables irq and completes qc atomically and convert all polling functions. Note: atapi_packet_task() didn't use to turn irq back on or clear ATA_FLAG_NOINTR on error exits. This patch makes it use ata_poll_qc_complete which does both. Note: With this change, ALL invocations of ata_qc_complete() are now done under host_set lock. Signed-off-by:

Tejun Heo <htejun@gmail.com> Signed-off-by:

Jeff Garzik <jgarzik@pobox.com>

drivers/scsi/libata-core.c

+24 −10

Original line number	Diff line number	Diff line
		@@ -2401,6 +2401,26 @@ static int ata_sg_setup(struct ata_queued_cmd *qc)
		return 0;
		}

		/**
		* ata_poll_qc_complete - turn irq back on and finish qc
		* @qc: Command to complete
		* @drv_stat: ATA status register content
		*
		* LOCKING:
		* None. (grabs host lock)
		*/

		void ata_poll_qc_complete(struct ata_queued_cmd *qc, u8 drv_stat)
		{
		struct ata_port *ap = qc->ap;

		spin_lock_irq(&ap->host_set->lock);
		ap->flags &= ~ATA_FLAG_NOINTR;
		ata_irq_on(ap);
		ata_qc_complete(qc, drv_stat);
		spin_unlock_irq(&ap->host_set->lock);
		}

		/**
		* ata_pio_poll -
		* @ap:
		@@ -2492,9 +2512,7 @@ static void ata_pio_complete (struct ata_port *ap)

		ap->pio_task_state = PIO_ST_IDLE;

		ata_irq_on(ap);

		ata_qc_complete(qc, drv_stat);
		ata_poll_qc_complete(qc, drv_stat);
		}


		@@ -2844,9 +2862,7 @@ static void ata_pio_block(struct ata_port *ap)
		if ((status & ATA_DRQ) == 0) {
		ap->pio_task_state = PIO_ST_IDLE;

		ata_irq_on(ap);

		ata_qc_complete(qc, status);
		ata_poll_qc_complete(qc, status);
		return;
		}

		@@ -2876,9 +2892,7 @@ static void ata_pio_error(struct ata_port *ap)

		ap->pio_task_state = PIO_ST_IDLE;

		ata_irq_on(ap);

		ata_qc_complete(qc, drv_stat \| ATA_ERR);
		ata_poll_qc_complete(qc, drv_stat \| ATA_ERR);
		}

		static void ata_pio_task(void *_data)
		@@ -3791,7 +3805,7 @@ static void atapi_packet_task(void *_data)
		return;

		err_out:
		ata_qc_complete(qc, ATA_ERR);
		ata_poll_qc_complete(qc, ATA_ERR);
		}

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