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b=lK+GSX9W2dxse2HyFd8Jo6d+QKzGF9OlBj1oecrFz4S6AZ5ZGvYj0U29jK2r3rSvf y2TN2zWRzzB2lTP1HSeQnY0jMt0kqpisBLhDZNrhy817BlFlks+7Zv0bBXcO3PCQXm xqIeN3l6gl+qQOdokjB/nVcwI01CDenCOl1Y3LMD6O8NfoCc9wls0F1EUSqVI9GWFE XmnNqWZwPVUy1buWspkA61VQgO6+YC/Fzbo/22mPe1Im0l95a/gqOA/GE+Xb7jUohS vikK1LusV/6HXx2EHBKcO5zbLmR7/9McSFlyM8CGcXs8L/X9Tsj+dYps1DLFoz76jh 97TRZyhe2Wegw== Received: by letrec.thunk.org (Postfix, from userid 15806) id 9B5FD8C01FA; Wed, 26 Apr 2023 19:16:16 -0400 (EDT) Date: Wed, 26 Apr 2023 19:16:16 -0400 From: "Theodore Ts'o" To: Nick Desaulniers Cc: Linus Torvalds , Nathan Chancellor , linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [GIT PULL] ext4 changes for the 6.4 merge window Message-ID: References: <20230425041838.GA150312@mit.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 52B3980017 X-Stat-Signature: ug1gzk9t4zu4gz4fx9xw8ydar3ekdoku X-HE-Tag: 1682550984-560946 X-HE-Meta: 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 JUnHP5WW RzXR1Esgj66nZPD/KXl5ipqPuyhkcniTz4dP4atMSQZrFM6vflqLcBGzVS6w0cRSdHnEyxBpQkMwCYLNEbV9rZNmEKmM6H30xO1ssayyKKahbBEyAmWXd+KXSovMgcDmmlaC220gpRqI2m3V8iX92vDL0d37JA4GIftPY0TsH9WsAO86OiAV4djzjqJdO1A1ZrvazTH2ZeAxH5gyq0SiAj7KKeA== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000124, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Apr 26, 2023 at 03:07:48PM -0700, Nick Desaulniers wrote: > Is this what you had in mind? > ``` > $ cat linus.c > #define NULL ((void*)0) > > void * _Nonnull foo (void) { > return &foo; > } > > void bar (void) { > if (foo() == NULL) // maybe should warn that foo() returns _Nonnull? > bar(); > } > > $ clang linus.c -fsyntax-only > linus.c:8:15: warning: comparison of _Nonnull function call 'foo' > equal to a null pointer is always false Ideally, the warning should also fire in this case: if (!foo()) { bar(); } And of course, what if the code does this: p = foo(); if (p) { quux(); } Would these also be considered implicit comparisons to a NULL pointer? - Ted