Merge "usb: gadget: storage: Prevent race condition from stalling thread" (2e873d60) · Commits · e / devices / android_kernel_xiaomi_markw

drivers/usb/gadget/function/f_mass_storage.c

+44 −1

Original line number	Diff line number	Diff line
		@@ -646,12 +646,18 @@ static int sleep_thread(struct fsg_common *common, bool can_freeze)
		rc = -EINTR;
		break;
		}
		if (common->thread_wakeup_needed)
		spin_lock_irq(&common->lock);
		if (common->thread_wakeup_needed) {
		spin_unlock_irq(&common->lock);
		break;
		}
		spin_unlock_irq(&common->lock);
		schedule();
		}
		__set_current_state(TASK_RUNNING);
		spin_lock_irq(&common->lock);
		common->thread_wakeup_needed = 0;
		spin_unlock_irq(&common->lock);
		smp_rmb(); /* ensure the latest bh->state is visible */
		return rc;
		}
		@@ -712,12 +718,17 @@ static int do_read(struct fsg_common *common)
		curlun->file_length - file_offset);

		/* Wait for the next buffer to become available */
		spin_lock_irq(&common->lock);
		bh = common->next_buffhd_to_fill;
		while (bh->state != BUF_STATE_EMPTY) {
		spin_unlock_irq(&common->lock);
		rc = sleep_thread(common, false);
		if (rc)
		return rc;

		spin_lock_irq(&common->lock);
		}
		spin_unlock_irq(&common->lock);

		/*
		* If we were asked to read past the end of file,
		@@ -729,8 +740,10 @@ static int do_read(struct fsg_common *common)
		curlun->sense_data_info =
		file_offset >> curlun->blkbits;
		curlun->info_valid = 1;
		spin_lock_irq(&common->lock);
		bh->inreq->length = 0;
		bh->state = BUF_STATE_FULL;
		spin_unlock_irq(&common->lock);
		break;
		}

		@@ -768,8 +781,10 @@ static int do_read(struct fsg_common *common)
		* equal to the buffer size, which is divisible by the
		* bulk-in maxpacket size.
		*/
		spin_lock_irq(&common->lock);
		bh->inreq->length = nread;
		bh->state = BUF_STATE_FULL;
		spin_unlock_irq(&common->lock);

		/* If an error occurred, report it and its position */
		if (nread < amount) {
		@@ -1713,12 +1728,17 @@ static int send_status(struct fsg_common *common)
		u32 sd, sdinfo = 0;

		/* Wait for the next buffer to become available */
		spin_lock_irq(&common->lock);
		bh = common->next_buffhd_to_fill;
		while (bh->state != BUF_STATE_EMPTY) {
		spin_unlock_irq(&common->lock);
		rc = sleep_thread(common, true);
		if (rc)
		return rc;

		spin_lock_irq(&common->lock);
		}
		spin_unlock_irq(&common->lock);

		if (curlun) {
		sd = curlun->sense_data;
		@@ -1924,13 +1944,19 @@ static int do_scsi_command(struct fsg_common *common)
		dump_cdb(common);

		/* Wait for the next buffer to become available for data or status */
		spin_lock_irq(&common->lock);
		bh = common->next_buffhd_to_fill;
		common->next_buffhd_to_drain = bh;
		while (bh->state != BUF_STATE_EMPTY) {
		spin_unlock_irq(&common->lock);
		rc = sleep_thread(common, true);
		if (rc)
		return rc;

		spin_lock_irq(&common->lock);
		}
		spin_unlock_irq(&common->lock);

		common->phase_error = 0;
		common->short_packet_received = 0;

		@@ -2271,12 +2297,17 @@ static int get_next_command(struct fsg_common *common)
		int rc = 0;

		/* Wait for the next buffer to become available */
		spin_lock_irq(&common->lock);
		bh = common->next_buffhd_to_fill;
		while (bh->state != BUF_STATE_EMPTY) {
		spin_unlock_irq(&common->lock);
		rc = sleep_thread(common, true);
		if (rc)
		return rc;

		spin_lock_irq(&common->lock);
		}
		spin_unlock_irq(&common->lock);

		/* Queue a request to read a Bulk-only CBW */
		set_bulk_out_req_length(common, bh, US_BULK_CB_WRAP_LEN);
		@@ -2291,14 +2322,23 @@ static int get_next_command(struct fsg_common *common)
		*/

		/* Wait for the CBW to arrive */
		spin_lock_irq(&common->lock);
		while (bh->state != BUF_STATE_FULL) {
		spin_unlock_irq(&common->lock);
		rc = sleep_thread(common, true);
		if (rc)
		return rc;

		spin_lock_irq(&common->lock);
		}
		spin_unlock_irq(&common->lock);

		smp_rmb();
		rc = fsg_is_set(common) ? received_cbw(common->fsg, bh) : -EIO;

		spin_lock_irq(&common->lock);
		bh->state = BUF_STATE_EMPTY;
		spin_unlock_irq(&common->lock);

		return rc;
		}
		@@ -2489,10 +2529,13 @@ static void handle_exception(struct fsg_common *common)
		/* Wait until everything is idle */
		for (;;) {
		int num_active = 0;
		spin_lock_irq(&common->lock);
		for (i = 0; i < common->fsg_num_buffers; ++i) {
		bh = &common->buffhds[i];
		num_active += bh->inreq_busy + bh->outreq_busy;
		}
		spin_unlock_irq(&common->lock);

		if (num_active == 0)
		break;
		if (sleep_thread(common, true))