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Thu, 28 Aug 2025 10:34:56 -0700 (PDT) Date: Fri, 29 Aug 2025 01:34:53 +0800 From: Kuan-Wei Chiu To: Guan-Chun Wu <409411716@gms.tku.edu.tw> Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] btree: simplify merge logic by using btree_last() return value Message-ID: References: <20250826161741.686704-1-409411716@gms.tku.edu.tw> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250826161741.686704-1-409411716@gms.tku.edu.tw> Hi Guan-Chun, On Wed, Aug 27, 2025 at 12:17:41AM +0800, Guan-Chun Wu wrote: > Previously btree_merge() called btree_last() only to test existence, > then performed an extra btree_lookup() to fetch the value. This patch > changes it to directly use the value returned by btree_last(), avoiding > redundant lookups and simplifying the merge loop. > > v2: > - Update subject to clarify this is a simplification, not a bug fix For future reference, please put version-to-version changelogs (e.g. v1 -> v2 notes) between --- and the diffstat. [1] That way they are not recorded in the permanent commit message but still visible during review. [1]: https://www.kernel.org/doc/html/v6.12/process/submitting-patches.html#the-canonical-patch-format Regards, Kuan-Wei > > Signed-off-by: Guan-Chun Wu <409411716@gms.tku.edu.tw> > --- > lib/btree.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/lib/btree.c b/lib/btree.c > index bb81d3393ac5..9c80c0c7bba8 100644 > --- a/lib/btree.c > +++ b/lib/btree.c > @@ -653,9 +653,9 @@ int btree_merge(struct btree_head *target, struct btree_head *victim, > * walks to remove a single object from the victim. > */ > for (;;) { > - if (!btree_last(victim, geo, key)) > + val = btree_last(victim, geo, key); > + if (!val) > break; > - val = btree_lookup(victim, geo, key); > err = btree_insert(target, geo, key, val, gfp); > if (err) > return err; > -- > 2.34.1 > >