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Groups > linux.kernel > #1368899 > unrolled thread
| Started by | Peter Hurley <peter@hurleysoftware.com> |
|---|---|
| First post | 2016-04-01 02:30 +0200 |
| Last post | 2016-04-01 05:50 +0200 |
| Articles | 3 — 2 participants |
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Re: linux-next: manual merge of the tty tree with the tty.current tree Peter Hurley <peter@hurleysoftware.com> - 2016-04-01 02:30 +0200
[PATCH] tty: Fix merge of "tty: Refactor tty_open()" Peter Hurley <peter@hurleysoftware.com> - 2016-04-01 02:50 +0200
Re: linux-next: manual merge of the tty tree with the tty.current tree Greg KH <greg@kroah.com> - 2016-04-01 05:50 +0200
| From | Peter Hurley <peter@hurleysoftware.com> |
|---|---|
| Date | 2016-04-01 02:30 +0200 |
| Subject | Re: linux-next: manual merge of the tty tree with the tty.current tree |
| Message-ID | <riV8m-4z1-9@gated-at.bofh.it> |
On Sun, Feb 7, 2016 at 6:21 PM, Greg KH <greg@kroah.com> wrote:
> On Mon, Feb 08, 2016 at 01:16:29PM +1100, Stephen Rothwell wrote:
>> Hi Greg,
>>
>> Today's linux-next merge of the tty tree got a conflict in:
>>
>> drivers/tty/tty_io.c
>>
>> between commit:
>>
>> e9036d066236 ("tty: Drop krefs for interrupted tty lock")
>>
>> from the tty.current tree and commit:
>>
>> d6203d0c7b73 ("tty: Refactor tty_open()")
>>
>> from the tty tree.
>>
>> I fixed it up (I think - see below) and can carry the fix as necessary
>> (no action is required).
>>
>> --
>> Cheers,
>> Stephen Rothwell
>>
>> diff --cc drivers/tty/tty_io.c
>> index a7eacef1bd22,8d26ed79bb4c..000000000000
>> --- a/drivers/tty/tty_io.c
>> +++ b/drivers/tty/tty_io.c
>> @@@ -2004,6 -2009,69 +2009,68 @@@ static struct tty_driver *tty_lookup_dr
>> }
>>
>> /**
>> + * tty_open_by_driver - open a tty device
>> + * @device: dev_t of device to open
>> + * @inode: inode of device file
>> + * @filp: file pointer to tty
>> + *
>> + * Performs the driver lookup, checks for a reopen, or otherwise
>> + * performs the first-time tty initialization.
>> + *
>> + * Returns the locked initialized or re-opened &tty_struct
>> + *
>> + * Claims the global tty_mutex to serialize:
>> + * - concurrent first-time tty initialization
>> + * - concurrent tty driver removal w/ lookup
>> + * - concurrent tty removal from driver table
>> + */
>> + static struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode,
>> + struct file *filp)
>> + {
>> + struct tty_struct *tty;
>> + struct tty_driver *driver = NULL;
>> + int index = -1;
>> + int retval;
>> +
>> + mutex_lock(&tty_mutex);
>> + driver = tty_lookup_driver(device, filp, &index);
>> + if (IS_ERR(driver)) {
>> + mutex_unlock(&tty_mutex);
>> + return ERR_CAST(driver);
>> + }
>> +
>> + /* check whether we're reopening an existing tty */
>> + tty = tty_driver_lookup_tty(driver, inode, index);
>> + if (IS_ERR(tty)) {
>> + mutex_unlock(&tty_mutex);
>> + goto out;
>> + }
>> +
>> + if (tty) {
>> + mutex_unlock(&tty_mutex);
>> + retval = tty_lock_interruptible(tty);
>> ++ tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */
>> + if (retval) {
>> + if (retval == -EINTR)
>> + retval = -ERESTARTSYS;
>> + tty = ERR_PTR(retval);
>> + goto out;
>> + }
>> - /* safe to drop the kref from tty_driver_lookup_tty() */
>> - tty_kref_put(tty);
>> + retval = tty_reopen(tty);
>> + if (retval < 0) {
>> + tty_unlock(tty);
>> + tty = ERR_PTR(retval);
>> + }
>> + } else { /* Returns with the tty_lock held for now */
>> + tty = tty_init_dev(driver, index);
>> + mutex_unlock(&tty_mutex);
>> + }
>> + out:
>> + tty_driver_kref_put(driver);
>> + return tty;
>> + }
>> +
>> + /**
>> * tty_open - open a tty device
>> * @inode: inode of device file
>> * @filp: file pointer to tty
>
> Peter warned me this was going to happen...
>
> Peter, is the merge above correct?
Greg, this merge correction did not make it into 4.6-rc1.
Was I supposed to send a separate patch for this merge change?
Should I now?
Regards,
Peter Hurley
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| From | Peter Hurley <peter@hurleysoftware.com> |
|---|---|
| Date | 2016-04-01 02:50 +0200 |
| Subject | [PATCH] tty: Fix merge of "tty: Refactor tty_open()" |
| Message-ID | <riVrI-4Iz-9@gated-at.bofh.it> |
| In reply to | #1368899 |
Commit e9036d066236 ("tty: Drop krefs for interrupted tty lock")
fixed a tty reference counting problem introduced in
commit 0bfd464d3fdd ("tty: Wait interruptibly for tty lock on reopen"),
so v4.5.0 is correct.
However, commit d6203d0c7b73 ("tty: Refactor tty_open()") moved the
relevant code for 4.6-rc1; correct the merge.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
---
drivers/tty/tty_io.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 8d26ed7..c14c45f 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -2049,14 +2049,13 @@ static struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode,
if (tty) {
mutex_unlock(&tty_mutex);
retval = tty_lock_interruptible(tty);
+ tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */
if (retval) {
if (retval == -EINTR)
retval = -ERESTARTSYS;
tty = ERR_PTR(retval);
goto out;
}
- /* safe to drop the kref from tty_driver_lookup_tty() */
- tty_kref_put(tty);
retval = tty_reopen(tty);
if (retval < 0) {
tty_unlock(tty);
--
2.8.0
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| From | Greg KH <greg@kroah.com> |
|---|---|
| Date | 2016-04-01 05:50 +0200 |
| Subject | Re: linux-next: manual merge of the tty tree with the tty.current tree |
| Message-ID | <riYfU-6VQ-5@gated-at.bofh.it> |
| In reply to | #1368899 |
On Thu, Mar 31, 2016 at 05:23:27PM -0700, Peter Hurley wrote:
> On Sun, Feb 7, 2016 at 6:21 PM, Greg KH <greg@kroah.com> wrote:
> > On Mon, Feb 08, 2016 at 01:16:29PM +1100, Stephen Rothwell wrote:
> >> Hi Greg,
> >>
> >> Today's linux-next merge of the tty tree got a conflict in:
> >>
> >> drivers/tty/tty_io.c
> >>
> >> between commit:
> >>
> >> e9036d066236 ("tty: Drop krefs for interrupted tty lock")
> >>
> >> from the tty.current tree and commit:
> >>
> >> d6203d0c7b73 ("tty: Refactor tty_open()")
> >>
> >> from the tty tree.
> >>
> >> I fixed it up (I think - see below) and can carry the fix as necessary
> >> (no action is required).
> >>
> >> --
> >> Cheers,
> >> Stephen Rothwell
> >>
> >> diff --cc drivers/tty/tty_io.c
> >> index a7eacef1bd22,8d26ed79bb4c..000000000000
> >> --- a/drivers/tty/tty_io.c
> >> +++ b/drivers/tty/tty_io.c
> >> @@@ -2004,6 -2009,69 +2009,68 @@@ static struct tty_driver *tty_lookup_dr
> >> }
> >>
> >> /**
> >> + * tty_open_by_driver - open a tty device
> >> + * @device: dev_t of device to open
> >> + * @inode: inode of device file
> >> + * @filp: file pointer to tty
> >> + *
> >> + * Performs the driver lookup, checks for a reopen, or otherwise
> >> + * performs the first-time tty initialization.
> >> + *
> >> + * Returns the locked initialized or re-opened &tty_struct
> >> + *
> >> + * Claims the global tty_mutex to serialize:
> >> + * - concurrent first-time tty initialization
> >> + * - concurrent tty driver removal w/ lookup
> >> + * - concurrent tty removal from driver table
> >> + */
> >> + static struct tty_struct *tty_open_by_driver(dev_t device, struct inode *inode,
> >> + struct file *filp)
> >> + {
> >> + struct tty_struct *tty;
> >> + struct tty_driver *driver = NULL;
> >> + int index = -1;
> >> + int retval;
> >> +
> >> + mutex_lock(&tty_mutex);
> >> + driver = tty_lookup_driver(device, filp, &index);
> >> + if (IS_ERR(driver)) {
> >> + mutex_unlock(&tty_mutex);
> >> + return ERR_CAST(driver);
> >> + }
> >> +
> >> + /* check whether we're reopening an existing tty */
> >> + tty = tty_driver_lookup_tty(driver, inode, index);
> >> + if (IS_ERR(tty)) {
> >> + mutex_unlock(&tty_mutex);
> >> + goto out;
> >> + }
> >> +
> >> + if (tty) {
> >> + mutex_unlock(&tty_mutex);
> >> + retval = tty_lock_interruptible(tty);
> >> ++ tty_kref_put(tty); /* drop kref from tty_driver_lookup_tty() */
> >> + if (retval) {
> >> + if (retval == -EINTR)
> >> + retval = -ERESTARTSYS;
> >> + tty = ERR_PTR(retval);
> >> + goto out;
> >> + }
> >> - /* safe to drop the kref from tty_driver_lookup_tty() */
> >> - tty_kref_put(tty);
> >> + retval = tty_reopen(tty);
> >> + if (retval < 0) {
> >> + tty_unlock(tty);
> >> + tty = ERR_PTR(retval);
> >> + }
> >> + } else { /* Returns with the tty_lock held for now */
> >> + tty = tty_init_dev(driver, index);
> >> + mutex_unlock(&tty_mutex);
> >> + }
> >> + out:
> >> + tty_driver_kref_put(driver);
> >> + return tty;
> >> + }
> >> +
> >> + /**
> >> * tty_open - open a tty device
> >> * @inode: inode of device file
> >> * @filp: file pointer to tty
> >
> > Peter warned me this was going to happen...
> >
> > Peter, is the merge above correct?
>
> Greg, this merge correction did not make it into 4.6-rc1.
>
> Was I supposed to send a separate patch for this merge change?
> Should I now?
The patch you sent should be fine, thanks.
greg k-h
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