linux_dsm_epyc7002/include/linux/nbd.h

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/*
* 1999 Copyright (C) Pavel Machek, pavel@ucw.cz. This code is GPL.
* 1999/11/04 Copyright (C) 1999 VMware, Inc. (Regis "HPReg" Duchesne)
* Made nbd_end_request() use the io_request_lock
* 2001 Copyright (C) Steven Whitehouse
* New nbd_end_request() for compatibility with new linux block
* layer code.
* 2003/06/24 Louis D. Langholtz <ldl@aros.net>
* Removed unneeded blksize_bits field from nbd_device struct.
* Cleanup PARANOIA usage & code.
* 2004/02/19 Paul Clements
* Removed PARANOIA, plus various cleanup and comments
*/
#ifndef LINUX_NBD_H
#define LINUX_NBD_H
[PATCH] nbd: fix TX/RX race condition Janos Haar of First NetCenter Bt. reported numerous crashes involving the NBD driver. With his help, this was tracked down to bogus bio vectors which in turn was the result of a race condition between the receive/transmit routines in the NBD driver. The bug manifests itself like this: CPU0 CPU1 do_nbd_request add req to queuelist nbd_send_request send req head for each bio kmap send nbd_read_stat nbd_find_request nbd_end_request kunmap When CPU1 finishes nbd_end_request, the request and all its associated bio's are freed. So when CPU0 calls kunmap whose argument is derived from the last bio, it may crash. Under normal circumstances, the race occurs only on the last bio. However, if an error is encountered on the remote NBD server (such as an incorrect magic number in the request), or if there were a bug in the server, it is possible for the nbd_end_request to occur any time after the request's addition to the queuelist. The following patch fixes this problem by making sure that requests are not added to the queuelist until after they have been completed transmission. In order for the receiving side to be ready for responses involving requests still being transmitted, the patch introduces the concept of the active request. When a response matches the current active request, its processing is delayed until after the tranmission has come to a stop. This has been tested by Janos and it has been successful in curing this race condition. From: Herbert Xu <herbert@gondor.apana.org.au> Here is an updated patch which removes the active_req wait in nbd_clear_queue and the associated memory barrier. I've also clarified this in the comment. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Cc: <djani22@dynamicweb.hu> Cc: Paul Clements <Paul.Clements@SteelEye.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 15:09:47 +07:00
#include <linux/wait.h>
#include <linux/mutex.h>
#include <uapi/linux/nbd.h>
[PATCH] nbd: fix TX/RX race condition Janos Haar of First NetCenter Bt. reported numerous crashes involving the NBD driver. With his help, this was tracked down to bogus bio vectors which in turn was the result of a race condition between the receive/transmit routines in the NBD driver. The bug manifests itself like this: CPU0 CPU1 do_nbd_request add req to queuelist nbd_send_request send req head for each bio kmap send nbd_read_stat nbd_find_request nbd_end_request kunmap When CPU1 finishes nbd_end_request, the request and all its associated bio's are freed. So when CPU0 calls kunmap whose argument is derived from the last bio, it may crash. Under normal circumstances, the race occurs only on the last bio. However, if an error is encountered on the remote NBD server (such as an incorrect magic number in the request), or if there were a bug in the server, it is possible for the nbd_end_request to occur any time after the request's addition to the queuelist. The following patch fixes this problem by making sure that requests are not added to the queuelist until after they have been completed transmission. In order for the receiving side to be ready for responses involving requests still being transmitted, the patch introduces the concept of the active request. When a response matches the current active request, its processing is delayed until after the tranmission has come to a stop. This has been tested by Janos and it has been successful in curing this race condition. From: Herbert Xu <herbert@gondor.apana.org.au> Here is an updated patch which removes the active_req wait in nbd_clear_queue and the associated memory barrier. I've also clarified this in the comment. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Cc: <djani22@dynamicweb.hu> Cc: Paul Clements <Paul.Clements@SteelEye.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 15:09:47 +07:00
struct request;
struct nbd_device {
int flags;
int harderror; /* Code of hard error */
struct socket * sock; /* If == NULL, device is not ready, yet */
int magic;
[PATCH] nbd: fix TX/RX race condition Janos Haar of First NetCenter Bt. reported numerous crashes involving the NBD driver. With his help, this was tracked down to bogus bio vectors which in turn was the result of a race condition between the receive/transmit routines in the NBD driver. The bug manifests itself like this: CPU0 CPU1 do_nbd_request add req to queuelist nbd_send_request send req head for each bio kmap send nbd_read_stat nbd_find_request nbd_end_request kunmap When CPU1 finishes nbd_end_request, the request and all its associated bio's are freed. So when CPU0 calls kunmap whose argument is derived from the last bio, it may crash. Under normal circumstances, the race occurs only on the last bio. However, if an error is encountered on the remote NBD server (such as an incorrect magic number in the request), or if there were a bug in the server, it is possible for the nbd_end_request to occur any time after the request's addition to the queuelist. The following patch fixes this problem by making sure that requests are not added to the queuelist until after they have been completed transmission. In order for the receiving side to be ready for responses involving requests still being transmitted, the patch introduces the concept of the active request. When a response matches the current active request, its processing is delayed until after the tranmission has come to a stop. This has been tested by Janos and it has been successful in curing this race condition. From: Herbert Xu <herbert@gondor.apana.org.au> Here is an updated patch which removes the active_req wait in nbd_clear_queue and the associated memory barrier. I've also clarified this in the comment. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Cc: <djani22@dynamicweb.hu> Cc: Paul Clements <Paul.Clements@SteelEye.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 15:09:47 +07:00
spinlock_t queue_lock;
struct list_head queue_head; /* Requests waiting result */
[PATCH] nbd: fix TX/RX race condition Janos Haar of First NetCenter Bt. reported numerous crashes involving the NBD driver. With his help, this was tracked down to bogus bio vectors which in turn was the result of a race condition between the receive/transmit routines in the NBD driver. The bug manifests itself like this: CPU0 CPU1 do_nbd_request add req to queuelist nbd_send_request send req head for each bio kmap send nbd_read_stat nbd_find_request nbd_end_request kunmap When CPU1 finishes nbd_end_request, the request and all its associated bio's are freed. So when CPU0 calls kunmap whose argument is derived from the last bio, it may crash. Under normal circumstances, the race occurs only on the last bio. However, if an error is encountered on the remote NBD server (such as an incorrect magic number in the request), or if there were a bug in the server, it is possible for the nbd_end_request to occur any time after the request's addition to the queuelist. The following patch fixes this problem by making sure that requests are not added to the queuelist until after they have been completed transmission. In order for the receiving side to be ready for responses involving requests still being transmitted, the patch introduces the concept of the active request. When a response matches the current active request, its processing is delayed until after the tranmission has come to a stop. This has been tested by Janos and it has been successful in curing this race condition. From: Herbert Xu <herbert@gondor.apana.org.au> Here is an updated patch which removes the active_req wait in nbd_clear_queue and the associated memory barrier. I've also clarified this in the comment. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Cc: <djani22@dynamicweb.hu> Cc: Paul Clements <Paul.Clements@SteelEye.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 15:09:47 +07:00
struct request *active_req;
wait_queue_head_t active_wq;
struct list_head waiting_queue; /* Requests to be sent */
wait_queue_head_t waiting_wq;
[PATCH] nbd: fix TX/RX race condition Janos Haar of First NetCenter Bt. reported numerous crashes involving the NBD driver. With his help, this was tracked down to bogus bio vectors which in turn was the result of a race condition between the receive/transmit routines in the NBD driver. The bug manifests itself like this: CPU0 CPU1 do_nbd_request add req to queuelist nbd_send_request send req head for each bio kmap send nbd_read_stat nbd_find_request nbd_end_request kunmap When CPU1 finishes nbd_end_request, the request and all its associated bio's are freed. So when CPU0 calls kunmap whose argument is derived from the last bio, it may crash. Under normal circumstances, the race occurs only on the last bio. However, if an error is encountered on the remote NBD server (such as an incorrect magic number in the request), or if there were a bug in the server, it is possible for the nbd_end_request to occur any time after the request's addition to the queuelist. The following patch fixes this problem by making sure that requests are not added to the queuelist until after they have been completed transmission. In order for the receiving side to be ready for responses involving requests still being transmitted, the patch introduces the concept of the active request. When a response matches the current active request, its processing is delayed until after the tranmission has come to a stop. This has been tested by Janos and it has been successful in curing this race condition. From: Herbert Xu <herbert@gondor.apana.org.au> Here is an updated patch which removes the active_req wait in nbd_clear_queue and the associated memory barrier. I've also clarified this in the comment. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Cc: <djani22@dynamicweb.hu> Cc: Paul Clements <Paul.Clements@SteelEye.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-06 15:09:47 +07:00
struct mutex tx_lock;
struct gendisk *disk;
int blksize;
u64 bytesize;
pid_t pid; /* pid of nbd-client, if attached */
int xmit_timeout;
int disconnect; /* a disconnect has been requested by user */
};
#endif