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[100.36.248.188]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-8cc80ded51esm100028546d6.17.2026.05.24.19.18.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 24 May 2026 19:18:13 -0700 (PDT) Date: Sun, 24 May 2026 22:18:12 -0400 From: Gregory Price To: Oleg Nesterov Cc: Alistair Popple , Andrew Morton , Byungchul Park , David Hildenbrand , Joshua Hahn , Matthew Brost , Rakie Kim , Ying Huang , Zi Yan , Jann Horn , Kees Cook , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/4] mm/mempolicy: kernel_migrate_pages: simplify the usage of put_task_struct() Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 3AFA4C0002 X-Stat-Signature: ufdh5ag6h7fgr6g3um8kijxmqai4kfdc X-HE-Tag: 1779675495-376218 X-HE-Meta: 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 lCxVU79x 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Sun, May 24, 2026 at 06:57:59PM +0200, Oleg Nesterov wrote: > kernel_migrate_pages() calls put_task_struct() twice; this complicates the > code. Move put_task_struct() to the unified exit path. This also allows us > to move the "out_put" label up and avoid another goto. > > Signed-off-by: Oleg Nesterov Reviewed-by: Gregory Price > --- > mm/mempolicy.c | 11 +++-------- > 1 file changed, 3 insertions(+), 8 deletions(-) > > diff --git a/mm/mempolicy.c b/mm/mempolicy.c > index 4e4421b22b59..4326dff16aa6 100644 > --- a/mm/mempolicy.c > +++ b/mm/mempolicy.c > @@ -1922,25 +1922,20 @@ static int kernel_migrate_pages(pid_t pid, unsigned long maxnode, > goto out_put; > > mm = get_task_mm(task); > - put_task_struct(task); > - > if (!mm) { > err = -EINVAL; > - goto out; > + goto out_put; > } > > err = do_migrate_pages(mm, old, new, > capable(CAP_SYS_NICE) ? MPOL_MF_MOVE_ALL : MPOL_MF_MOVE); > > mmput(mm); > +out_put: > + put_task_struct(task); > out: > NODEMASK_SCRATCH_FREE(scratch); > - > return err; > - > -out_put: > - put_task_struct(task); > - goto out; > } > > SYSCALL_DEFINE4(migrate_pages, pid_t, pid, unsigned long, maxnode, > -- > 2.52.0 >