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usb: diag_bridge: Fix error handling during disconnect

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usb_autopm_get_interface() returns an error if runtime PM is disabled,
yet this should not impede the ability to submit URBs. This can happen
just as the device is removed but the interface driver's disconnect()
routine has not been called. Thus any client wishing to call read or
write may errorneously continue to call and might eventually flood the
console with excessive printks which could cause a watchdog timeout. So
treat -EAGAIN and -EACCES as okay and only bail on other error values.

Also, rate-limit the printks associated with reading/writing on the
bridge to further avoid the possibility of excessive logging during
similar corner cases.

Finally, use -ENODEV as an indicator that read/write should halt. This
will handle the case when an URB fails to submit late in the device
disconnect stage, and the client should not attempt any more submissions.

CRs-fixed: 370694
Change-Id: Ia5f4a4bd7ed620eedd2cd00c117066b8c7eb4f8c
Signed-off-by: Jack Pham <jackp@codeaurora.org>
This commit is contained in:
Jack Pham
2012-06-14 19:00:31 -07:00
committed by Stephen Boyd
parent 467932fbfe
commit 8d2c272d6e
2 changed files with 17 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
drivers/char/diag/diagfwd_hsic.c
View File

@@ -16,6 +16,7 @@
#include <linux/diagchar.h>
#include <linux/sched.h>
#include <linux/err.h>
#include <linux/ratelimit.h>
#include <linux/workqueue.h>
#include <linux/pm_runtime.h>
#include <linux/platform_device.h>
@@ -55,7 +56,7 @@ static void diag_read_hsic_work_fn(struct work_struct *work)
err = diag_bridge_read((char *)driver->buf_in_hsic,
IN_BUF_SIZE);
if (err) {
pr_err("DIAG: Error initiating HSIC read, err: %d\n",
pr_err_ratelimited("DIAG: Error initiating HSIC read, err: %d\n",
err);
/*
* If the error is recoverable, then clear
@@ -63,7 +64,7 @@ static void diag_read_hsic_work_fn(struct work_struct *work)
* read on the next frame. Otherwise, don't
* resubmit a read on the next frame.
*/
if ((-ESHUTDOWN) != err)
if ((-ENODEV) != err)
driver->in_busy_hsic_read = 0;
}
}
@@ -373,14 +374,15 @@ static int diagfwd_read_complete_bridge(struct diag_request *diag_read_ptr)
err = diag_bridge_write(driver->usb_buf_mdm_out,
driver->read_len_mdm);
if (err) {
pr_err("DIAG: mdm data on hsic write err: %d\n", err);
pr_err_ratelimited("DIAG: mdm data on hsic write err: %d\n",
err);
/*
* If the error is recoverable, then clear
* the write flag, so we will resubmit a
* write on the next frame. Otherwise, don't
* resubmit a write on the next frame.
*/
if ((-ESHUTDOWN) != err)
if ((-ENODEV) != err)
driver->in_busy_hsic_write = 0;
}
}

21
drivers/usb/misc/diag_bridge.c
View File

@@ -21,6 +21,7 @@
#include <linux/module.h>
#include <linux/kref.h>
#include <linux/platform_device.h>
#include <linux/ratelimit.h>
#include <linux/uaccess.h>
#include <linux/usb.h>
#include <linux/debugfs.h>
@@ -97,7 +98,7 @@ static void diag_bridge_read_cb(struct urb *urb)
if (urb->status == -EPROTO) {
dev_err(&dev->udev->dev, "%s: proto error\n", __func__);
/* save error so that subsequent read/write returns ESHUTDOWN */
/* save error so that subsequent read/write returns ENODEV */
dev->err = urb->status;
kref_put(&dev->kref, diag_bridge_delete);
return;
@@ -140,7 +141,7 @@ int diag_bridge_read(char *data, int size)
/* if there was a previous unrecoverable error, just quit */
if (dev->err)
return -ESHUTDOWN;
return -ENODEV;
kref_get(&dev->kref);
@@ -152,8 +153,8 @@ int diag_bridge_read(char *data, int size)
}
ret = usb_autopm_get_interface(dev->ifc);
if (ret < 0) {
dev_err(&dev->udev->dev, "autopm_get failed:%d\n", ret);
if (ret < 0 && ret != -EAGAIN && ret != -EACCES) {
pr_err_ratelimited("read: autopm_get failed:%d", ret);
goto free_error;
}
@@ -165,7 +166,7 @@ int diag_bridge_read(char *data, int size)
ret = usb_submit_urb(urb, GFP_KERNEL);
if (ret) {
dev_err(&dev->udev->dev, "submitting urb failed err:%d\n", ret);
pr_err_ratelimited("submitting urb failed err:%d", ret);
dev->pending_reads--;
usb_unanchor_urb(urb);
}
@@ -191,7 +192,7 @@ static void diag_bridge_write_cb(struct urb *urb)
if (urb->status == -EPROTO) {
dev_err(&dev->udev->dev, "%s: proto error\n", __func__);
/* save error so that subsequent read/write returns ESHUTDOWN */
/* save error so that subsequent read/write returns ENODEV */
dev->err = urb->status;
kref_put(&dev->kref, diag_bridge_delete);
return;
@@ -234,7 +235,7 @@ int diag_bridge_write(char *data, int size)
/* if there was a previous unrecoverable error, just quit */
if (dev->err)
return -ESHUTDOWN;
return -ENODEV;
kref_get(&dev->kref);
@@ -246,8 +247,8 @@ int diag_bridge_write(char *data, int size)
}
ret = usb_autopm_get_interface(dev->ifc);
if (ret < 0) {
dev_err(&dev->udev->dev, "autopm_get failed:%d\n", ret);
if (ret < 0 && ret != -EAGAIN && ret != -EACCES) {
pr_err_ratelimited("write: autopm_get failed:%d", ret);
goto free_error;
}
@@ -259,7 +260,7 @@ int diag_bridge_write(char *data, int size)
ret = usb_submit_urb(urb, GFP_KERNEL);
if (ret) {
dev_err(&dev->udev->dev, "submitting urb failed err:%d\n", ret);
pr_err_ratelimited("submitting urb failed err:%d", ret);
dev->pending_writes--;
usb_unanchor_urb(urb);
usb_autopm_put_interface(dev->ifc);