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IB/umad: Return EPOLLERR in case of when device disassociated

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[ Upstream commit def4cd43f522253645b72c97181399c241b54536 ]

Currently, polling a umad device will always works, even if the device was
disassociated. A disassociated device should immediately return EPOLLERR
from poll(). Otherwise userspace is endlessly hung on poll() with no idea
that the device has been removed from the system.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Link: https://lore.kernel.org/r/20210125121339.837518-3-leon@kernel.org
Signed-off-by: Shay Drory <shayd@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Shay Drory 2021-01-25 14:13:39 +02:00 committed by Greg Kroah-Hartman
parent 16d7084da2
commit c22944505c
1 changed files with 10 additions and 0 deletions
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10
drivers/infiniband/core/user_mad.c
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@ -384,6 +384,11 @@ static ssize_t ib_umad_read(struct file *filp, char __user *buf,
mutex_lock(&file->mutex);
}
if (file->agents_dead) {
mutex_unlock(&file->mutex);
return -EIO;
}
packet = list_entry(file->recv_list.next, struct ib_umad_packet, list);
list_del(&packet->list);
@ -642,10 +647,14 @@ static __poll_t ib_umad_poll(struct file *filp, struct poll_table_struct *wait)
/* we will always be able to post a MAD send */
__poll_t mask = EPOLLOUT | EPOLLWRNORM;
mutex_lock(&file->mutex);
poll_wait(filp, &file->recv_wait, wait);
if (!list_empty(&file->recv_list))
mask |= EPOLLIN | EPOLLRDNORM;
if (file->agents_dead)
mask = EPOLLERR;
mutex_unlock(&file->mutex);
return mask;
}
@ -1262,6 +1271,7 @@ static void ib_umad_kill_port(struct ib_umad_port *port)
list_for_each_entry(file, &port->file_list, port_list) {
mutex_lock(&file->mutex);
file->agents_dead = 1;
wake_up_interruptible(&file->recv_wait);
mutex_unlock(&file->mutex);
for (id = 0; id < IB_UMAD_MAX_AGENTS; ++id)