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b=RZbb/QQNX947GjiHM/rvFaywRPpzDljnISz8So1ljEZ/W8YoDwh9lmfhKxMaOMllH f1jlg/Wwwwt18W5lDeTYH/n3A7Gd7uFOvx+37M0qlmGQOxoW72W9dV4EcO5YSCnhdy fsphlPKbsHtFVb1lVgLvymKWotj/WXeBweyF9/lEiTnKySR/AgEFuvA/JSYOr2fwYJ 8L1X8UJhd0OxFGuB1KiOr+6TIYDYA7FdE6cTZTIwZl92pXwKfiL7cjlLcLhpJuzfkO LzHutFm+dtFAQ0Db8AKfLt35gLgngcMPJisdPRfBWmsDj598nFYBxdENzGOtasOwYc upxzEE+ORsLrQ== Date: Fri, 11 Sep 2026 19:26:49 +0100 From: "Lorenzo Stoakes (ARM)" To: Suren Baghdasaryan Cc: akpm@linux-foundation.org, liam@infradead.org, vbabka@kernel.org, david@redhat.com, willy@infradead.org, jannh@google.com, paulmck@kernel.org, pfalcato@suse.de, xueyuan.chen21@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH v3 5/7] proc/task_mmu: change proc_get_vma() to stop returning gate VMA at the end Message-ID: References: <20260910234737.1340642-1-surenb@google.com> <20260910234737.1340642-6-surenb@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260910234737.1340642-6-surenb@google.com> X-Rspamd-Server: rspam04 X-Rspam-User: X-Stat-Signature: qoko3c7ce6frj85u53hbo7pa5a1cend9 X-Rspamd-Queue-Id: 98FB320009 X-HE-Tag: 1789151215-813464 X-HE-Meta: U2FsdGVkX1/6/lUCXDacUO0YrPDQ8vGYCJfzH6Wru0XQkrMBf5DXAvCvh6BSMAK/q4HLP+j8TrA44DDDGYFXC6tnyET75c6tf81cOrb0TXQWxnRI22kHEznPxgQaScv6VlS1ydsUb6+ICJpxk9Gz84vAsmmLy+giarkVJ5oszgEu8h2uQksyRkhfgbH1g1T7jbFcBabtmZtP+eYyXayzQ09/yVWQ24AiiGVpBwjGIdO++sUXBE+AI6n6/uK/KK+FfiPRq39YX1seTekCBvo8BFD0ihPmIlPQw47QfS82kE7q3zhycIO5EuCRi2w2CPGrziwDWmmSKLDeMeRcAfc5dX0ORZ0BAQmMwxmMM9OrYSzPJ4HjfJ7nAQsEXr/lyILScW8IoW+DjWjo4mfQNBnxWzNgZcvt0vbQUppR+iVIRlYKN0i+/9l1/uPmaqo7G1YeBRFkHbh+CmGyoel8MsRo1KegbLN+hWzBfNmTN53M43s1eBrZSkCw9B2w1jltSepJiShmnNf2RWPnmopwzSVfh1YGJrOCUPUW49JfXDdEMPIG6wV2VHRSt17/QEPJqB01Z9wT20HSnj1JAIcdYhjhpKkjWqT2OuLhFVLGkwFTO10xKNRUiYfjEYsJNIIOL0xxkyEl+mG+N+Fe2nABg4A4aYVIinSkkS6/xOtJNSPHnMrz8FmWF4NY6HSj7SZ6Yw/ja7BmXsTE+HRrBG6PAD0fy2hDTyCBFqVhuAXys2W30X+ViQTbwdxt/qEBAJhD1Y/P4+qgzZqHJVubKc+EJ7lhPYJNQaB6HY1jdoBneHYAtruollVQlkre6WGVN+2kZe4gzlEJ7lqtUyrtQ9uU2OPt6JruX1nNWt3ZV9Kn9Hg+PlCL4pep7Tv6V5TX8zwoYcXVqbk+S0y1QsXfmrJi7br+0NECx8ykNgNMHVeAwWm2Bb1AVWesHA8ahN0mQB9HrOvFB6M0308E4c6Gt0/VNoD RBh0yYSs GvXAC7dhREMLggoCJYdJkFaKFCKj+Se57c6PYhW9IIj6giMegdjI6tCkGcCF6yauaaZg3LW/3W7jSdkYlF55TlPuu8NzezdGZ600SevfAub/d0DuFViVShmkUvQZSZ3j6+mPFnc/BNKje7ILWEoB7UNXGcNM2E4uUn11USGHgRcX7+272ItMm3pqMRZFQz4Np2aEUnvOTxUJKQIaAPVl1oAKnASXSJnvT2k9q33j6axftsLK3CLGGsv8YjsGYBj5ctGuClf89Oawafd8D/XdCcJO7cU6Bhp3whreB1bbctwHtwPgvUI14pEbdN9JK00UE9ztl/kOrRUTZrfTkSt9pt8WuRKRmTo07qgQZQJxPVgVcUhN1ur7HI+7S6x91FHypLmKwuEqsdBtBNEWDgrR7E1otN/YmKMSsN905fctfesJsr50= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Sep 10, 2026 at 04:47:35PM -0700, Suren Baghdasaryan wrote: > proc_get_vma() returning gate VMA at the end is desirable for the its > current m_start/m_next callers, as they need to report a gate VMA at the > end of the address space. This behavior is very specific to these callers > and makes proc_get_vma() hard to use for other purposes. > > Move this usage-specific behavior into the callers themselves so that > proc_get_vma() returns either a valid VMA, an error or a NULL when no > more VMAs are available. This makes it more generic, simpler and usable > in the later patches. > > Signed-off-by: Suren Baghdasaryan Yes, very good change, thanks! Reviewed-by: Lorenzo Stoakes (ARM) > --- > fs/proc/task_mmu.c | 23 ++++++++++++++++++----- > 1 file changed, 18 insertions(+), 5 deletions(-) > > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c > index ecce7ce116cb..9a3c996c1d61 100644 > --- a/fs/proc/task_mmu.c > +++ b/fs/proc/task_mmu.c > @@ -236,9 +236,6 @@ static struct vm_area_struct *proc_get_vma(struct seq_file *m, loff_t *ppos) > * found the extended vma with the same vm_start. > */ > *ppos = vma->vm_end; > - } else { > - *ppos = SENTINEL_VMA_GATE; > - vma = get_gate_vma(priv->lock_ctx.mm); Yeah this is just so confusing as-was. > } > > return vma; > @@ -248,6 +245,7 @@ static void *m_start(struct seq_file *m, loff_t *ppos) > { > struct proc_maps_private *priv = m->private; > struct proc_maps_locking_ctx *lock_ctx; > + struct vm_area_struct *vma; > loff_t last_addr = *ppos; > struct mm_struct *mm; > > @@ -280,16 +278,31 @@ static void *m_start(struct seq_file *m, loff_t *ppos) > if (last_addr == SENTINEL_VMA_GATE) > return get_gate_vma(mm); > > - return proc_get_vma(m, ppos); > + vma = proc_get_vma(m, ppos); > + if (vma) > + return vma; > + > + /* Return gate VMA at the end */ > + *ppos = SENTINEL_VMA_GATE; > + return get_gate_vma(mm); > } > > static void *m_next(struct seq_file *m, void *v, loff_t *ppos) > { > + struct proc_maps_private *priv = m->private; > + struct vm_area_struct *vma; > + > if (*ppos == SENTINEL_VMA_GATE) { > *ppos = SENTINEL_VMA_END; > return NULL; > } > - return proc_get_vma(m, ppos); > + vma = proc_get_vma(m, ppos); > + if (vma) > + return vma; OK so I guess the logic is, iterate through every VMA, then once you run out, report the gate VMA. Makes sense. > + > + /* Return gate VMA at the end */ > + *ppos = SENTINEL_VMA_GATE; > + return get_gate_vma(priv->lock_ctx.mm); > } > > static void m_stop(struct seq_file *m, void *v) > -- > 2.55.0.1007.g17ff1f9808-goog > -- Cheers, Lorenzo