From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============3237251766655295463==" MIME-Version: 1.0 From: Krzysztof Kozlowski To: linux-nfc@lists.01.org Subject: Re: [PATCH v2 7/8] nfc: hci: pass callback data param as pointer in nci_request() Date: Fri, 30 Jul 2021 15:56:19 +0200 Message-ID: <53f89bae-fcb5-8e7c-0b03-effa156584fe@canonical.com> In-Reply-To: <20210730064922.078bd222@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> List-Id: --===============3237251766655295463== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable On 30/07/2021 15:49, Jakub Kicinski wrote: > On Fri, 30 Jul 2021 08:56:24 +0200 Krzysztof Kozlowski wrote: >> The nci_request() receives a callback function and unsigned long data >> argument "opt" which is passed to the callback. Almost all of the >> nci_request() callers pass pointer to a stack variable as data argument. >> Only few pass scalar value (e.g. u8). >> >> All such callbacks do not modify passed data argument and in previous >> commit they were made as const. However passing pointers via unsigned >> long removes the const annotation. The callback could simply cast >> unsigned long to a pointer to writeable memory. >> >> Use "const void *" as type of this "opt" argument to solve this and >> prevent modifying the pointed contents. This is also consistent with >> generic pattern of passing data arguments - via "void *". In few places >> passing scalar values, use casts via "unsigned long" to suppress any >> warnings. >> >> Signed-off-by: Krzysztof Kozlowski > = > This generates a bunch of warnings: > = > net/nfc/nci/core.c:381:51: warning: Using plain integer as NULL pointer > net/nfc/nci/core.c:388:50: warning: Using plain integer as NULL pointer > net/nfc/nci/core.c:494:57: warning: Using plain integer as NULL pointer > net/nfc/nci/core.c:520:65: warning: Using plain integer as NULL pointer > net/nfc/nci/core.c:570:44: warning: Using plain integer as NULL pointer > net/nfc/nci/core.c:815:34: warning: Using plain integer as NULL pointer > net/nfc/nci/core.c:856:50: warning: Using plain integer as NULL pointer Indeed. Not that code before was better - the logic was exactly the same. I might think more how to avoid these and maybe pass pointer to stack value (like in other cases). The 7/8 and 8/8 could be skipped in such case. > = > BTW applying this set will resolve the warnings introduced by applying > "part 2" out of order, right? No further action needed? Yes, it will resolve all warnings. No further action needed, at least I am not aware of any new issues. Best regards, Krzysztof --===============3237251766655295463==--