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Date: Thu, 27 Apr 2017 15:08:23 -0500
From: Steve French <smfrench@...il.com>
To: NeilBrown <neilb@...e.com>
Cc: Steve French <sfrench@...ba.org>,
"linux-cifs@...r.kernel.org" <linux-cifs@...r.kernel.org>,
LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] cifs: don't check for failure from mempool_alloc()
merged into cifs-2.6.git for-next
On Sun, Apr 9, 2017 at 9:08 PM, NeilBrown <neilb@...e.com> wrote:
>
> mempool_alloc() cannot fail if the gfp flags allow it to
> sleep, and both GFP_FS allows for sleeping.
>
> So these tests of the return value from mempool_alloc()
> cannot be needed.
>
> Signed-off-by: NeilBrown <neilb@...e.com>
> ---
> fs/cifs/misc.c | 14 +++++---------
> fs/cifs/smb2transport.c | 30 +++++++++++++-----------------
> fs/cifs/transport.c | 32 ++++++++++++++------------------
> 3 files changed, 32 insertions(+), 44 deletions(-)
>
> diff --git a/fs/cifs/misc.c b/fs/cifs/misc.c
> index d3fb11529ed9..843787850435 100644
> --- a/fs/cifs/misc.c
> +++ b/fs/cifs/misc.c
> @@ -167,13 +167,11 @@ cifs_buf_get(void)
>
> /* clear the first few header bytes */
> /* for most paths, more is cleared in header_assemble */
> - if (ret_buf) {
> - memset(ret_buf, 0, buf_size + 3);
> - atomic_inc(&bufAllocCount);
> + memset(ret_buf, 0, buf_size + 3);
> + atomic_inc(&bufAllocCount);
> #ifdef CONFIG_CIFS_STATS2
> - atomic_inc(&totBufAllocCount);
> + atomic_inc(&totBufAllocCount);
> #endif /* CONFIG_CIFS_STATS2 */
> - }
>
> return ret_buf;
> }
> @@ -201,15 +199,13 @@ cifs_small_buf_get(void)
> albeit slightly larger than necessary and maxbuffersize
> defaults to this and can not be bigger */
> ret_buf = mempool_alloc(cifs_sm_req_poolp, GFP_NOFS);
> - if (ret_buf) {
> /* No need to clear memory here, cleared in header assemble */
> /* memset(ret_buf, 0, sizeof(struct smb_hdr) + 27);*/
> - atomic_inc(&smBufAllocCount);
> + atomic_inc(&smBufAllocCount);
> #ifdef CONFIG_CIFS_STATS2
> - atomic_inc(&totSmBufAllocCount);
> + atomic_inc(&totSmBufAllocCount);
> #endif /* CONFIG_CIFS_STATS2 */
>
> - }
> return ret_buf;
> }
>
> diff --git a/fs/cifs/smb2transport.c b/fs/cifs/smb2transport.c
> index 506b67fc93d9..c69ec96e92ac 100644
> --- a/fs/cifs/smb2transport.c
> +++ b/fs/cifs/smb2transport.c
> @@ -538,23 +538,19 @@ smb2_mid_entry_alloc(const struct smb2_sync_hdr *shdr,
> }
>
> temp = mempool_alloc(cifs_mid_poolp, GFP_NOFS);
> - if (temp == NULL)
> - return temp;
> - else {
> - memset(temp, 0, sizeof(struct mid_q_entry));
> - temp->mid = le64_to_cpu(shdr->MessageId);
> - temp->pid = current->pid;
> - temp->command = shdr->Command; /* Always LE */
> - temp->when_alloc = jiffies;
> - temp->server = server;
> -
> - /*
> - * The default is for the mid to be synchronous, so the
> - * default callback just wakes up the current task.
> - */
> - temp->callback = cifs_wake_up_task;
> - temp->callback_data = current;
> - }
> + memset(temp, 0, sizeof(struct mid_q_entry));
> + temp->mid = le64_to_cpu(shdr->MessageId);
> + temp->pid = current->pid;
> + temp->command = shdr->Command; /* Always LE */
> + temp->when_alloc = jiffies;
> + temp->server = server;
> +
> + /*
> + * The default is for the mid to be synchronous, so the
> + * default callback just wakes up the current task.
> + */
> + temp->callback = cifs_wake_up_task;
> + temp->callback_data = current;
>
> atomic_inc(&midCount);
> temp->mid_state = MID_REQUEST_ALLOCATED;
> diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
> index f6e13a977fc8..4d64b5b8fc9c 100644
> --- a/fs/cifs/transport.c
> +++ b/fs/cifs/transport.c
> @@ -55,26 +55,22 @@ AllocMidQEntry(const struct smb_hdr *smb_buffer, struct TCP_Server_Info *server)
> }
>
> temp = mempool_alloc(cifs_mid_poolp, GFP_NOFS);
> - if (temp == NULL)
> - return temp;
> - else {
> - memset(temp, 0, sizeof(struct mid_q_entry));
> - temp->mid = get_mid(smb_buffer);
> - temp->pid = current->pid;
> - temp->command = cpu_to_le16(smb_buffer->Command);
> - cifs_dbg(FYI, "For smb_command %d\n", smb_buffer->Command);
> + memset(temp, 0, sizeof(struct mid_q_entry));
> + temp->mid = get_mid(smb_buffer);
> + temp->pid = current->pid;
> + temp->command = cpu_to_le16(smb_buffer->Command);
> + cifs_dbg(FYI, "For smb_command %d\n", smb_buffer->Command);
> /* do_gettimeofday(&temp->when_sent);*/ /* easier to use jiffies */
> - /* when mid allocated can be before when sent */
> - temp->when_alloc = jiffies;
> - temp->server = server;
> + /* when mid allocated can be before when sent */
> + temp->when_alloc = jiffies;
> + temp->server = server;
>
> - /*
> - * The default is for the mid to be synchronous, so the
> - * default callback just wakes up the current task.
> - */
> - temp->callback = cifs_wake_up_task;
> - temp->callback_data = current;
> - }
> + /*
> + * The default is for the mid to be synchronous, so the
> + * default callback just wakes up the current task.
> + */
> + temp->callback = cifs_wake_up_task;
> + temp->callback_data = current;
>
> atomic_inc(&midCount);
> temp->mid_state = MID_REQUEST_ALLOCATED;
> --
> 2.12.2
>
--
Thanks,
Steve
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