[06/16] block/nvme: Fix missing ERRP_GUARD() for error_prepend()

Commit Message

Zhao Liu Feb. 28, 2024, 4:37 p.m. UTC

From: Zhao Liu <[e-mail]>

As the comment in qapi/error, passing @errp to error_prepend() requires
ERRP_GUARD():

* = Why, when and how to use ERRP_GUARD() =
*
* Without ERRP_GUARD(), use of the @errp parameter is restricted:
...
* - It should not be passed to error_prepend(), error_vprepend() or
*   error_append_hint(), because that doesn't work with &error_fatal.
* ERRP_GUARD() lifts these restrictions.
*
* To use ERRP_GUARD(), add it right at the beginning of the function.
* @errp can then be used without worrying about the argument being
* NULL or &error_fatal.

ERRP_GUARD() could avoid the case when @errp is the pointer of
error_fatal, the user can't see this additional information, because
exit() happens in error_setg earlier than information is added [1].

In nvme.c, there're 3 functions passing @errp to error_prepend()
without ERRP_GUARD():
- nvme_init_queue()
- nvme_create_queue_pair()
- nvme_identify()

All these 3 functions take their @errp parameters from the
nvme_file_open(), which is a BlockDriver.bdrv_nvme() method and its
@errp points to its caller's local_err.

Though these 3 cases haven't trigger the issue like [1] said, to
follow the requirement of @errp, add missing ERRP_GUARD() at their
beginning.

[1]: Issue description in the commit message of commit ae7c80a7bd73
     ("error: New macro ERRP_GUARD()").

Cc: Stefan Hajnoczi <[e-mail]>
Cc: Fam Zheng <[e-mail]>
Cc: "Philippe Mathieu-Daudé" <[e-mail]>
Cc: Kevin Wolf <[e-mail]>
Cc: Hanna Reitz <[e-mail]>
Signed-off-by: Zhao Liu <[e-mail]>
---
 block/nvme.c | 3 +++
 1 file changed, 3 insertions(+)

Comments

Stefan Hajnoczi Feb. 28, 2024, 6:42 p.m. UTC | #1

On Thu, Feb 29, 2024 at 12:37:13AM +0800, Zhao Liu wrote:
> From: Zhao Liu <[e-mail]>
> 
> As the comment in qapi/error, passing @errp to error_prepend() requires
> ERRP_GUARD():
> 
> * = Why, when and how to use ERRP_GUARD() =
> *
> * Without ERRP_GUARD(), use of the @errp parameter is restricted:
> ...
> * - It should not be passed to error_prepend(), error_vprepend() or
> *   error_append_hint(), because that doesn't work with &error_fatal.
> * ERRP_GUARD() lifts these restrictions.
> *
> * To use ERRP_GUARD(), add it right at the beginning of the function.
> * @errp can then be used without worrying about the argument being
> * NULL or &error_fatal.
> 
> ERRP_GUARD() could avoid the case when @errp is the pointer of
> error_fatal, the user can't see this additional information, because
> exit() happens in error_setg earlier than information is added [1].
> 
> In nvme.c, there're 3 functions passing @errp to error_prepend()
> without ERRP_GUARD():
> - nvme_init_queue()
> - nvme_create_queue_pair()
> - nvme_identify()
> 
> All these 3 functions take their @errp parameters from the
> nvme_file_open(), which is a BlockDriver.bdrv_nvme() method and its
> @errp points to its caller's local_err.
> 
> Though these 3 cases haven't trigger the issue like [1] said, to
> follow the requirement of @errp, add missing ERRP_GUARD() at their
> beginning.
> 
> [1]: Issue description in the commit message of commit ae7c80a7bd73
>      ("error: New macro ERRP_GUARD()").
> 
> Cc: Stefan Hajnoczi <[e-mail]>
> Cc: Fam Zheng <[e-mail]>
> Cc: "Philippe Mathieu-Daudé" <[e-mail]>
> Cc: Kevin Wolf <[e-mail]>
> Cc: Hanna Reitz <[e-mail]>
> Signed-off-by: Zhao Liu <[e-mail]>
> ---
>  block/nvme.c | 3 +++
>  1 file changed, 3 insertions(+)

Reviewed-by: Stefan Hajnoczi <[e-mail]>

Patch

diff --git a/block/nvme.c b/block/nvme.c
index 0a0a0a6b36cd..3a3c6da73d29 100644
--- a/block/nvme.c
+++ b/block/nvme.c
@@ -168,6 +168,7 @@  static QemuOptsList runtime_opts = {
 static bool nvme_init_queue(BDRVNVMeState *s, NVMeQueue *q,
                             unsigned nentries, size_t entry_bytes, Error **errp)
 {
+    ERRP_GUARD();
     size_t bytes;
     int r;
 
@@ -221,6 +222,7 @@  static NVMeQueuePair *nvme_create_queue_pair(BDRVNVMeState *s,
                                              unsigned idx, size_t size,
                                              Error **errp)
 {
+    ERRP_GUARD();
     int i, r;
     NVMeQueuePair *q;
     uint64_t prp_list_iova;
@@ -535,6 +537,7 @@  static int nvme_admin_cmd_sync(BlockDriverState *bs, NvmeCmd *cmd)
 /* Returns true on success, false on failure. */
 static bool nvme_identify(BlockDriverState *bs, int namespace, Error **errp)
 {
+    ERRP_GUARD();
     BDRVNVMeState *s = bs->opaque;
     bool ret = false;
     QEMU_AUTO_VFREE union {