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[80.11.198.90]) by smtp.googlemail.com with ESMTPSA id q4sm100231882wja.6.2016.01.07.00.50.20 (version=TLSv1/SSLv3 cipher=OTHER); Thu, 07 Jan 2016 00:50:21 -0800 (PST) Subject: Re: [PATCH v2 4/7] device_tree: qemu_fdt_getprop converted to use the error API To: Peter Crosthwaite References: <1452093205-30167-1-git-send-email-eric.auger@linaro.org> <1452093205-30167-5-git-send-email-eric.auger@linaro.org> Cc: eric.auger@st.com, "qemu-devel@nongnu.org Developers" , qemu-arm , Peter Maydell , David Gibson , Alex Williamson , =?UTF-8?Q?Alex_Benn=c3=a9e?= , thuth@redhat.com, Patch Tracking , Christoffer Dall , Paolo Bonzini , b.reynal@virtualopensystems.com, suravee.suthikulpanit@amd.com, thomas.lendacky@amd.com From: Eric Auger Message-ID: <568E26C3.1070602@linaro.org> Date: Thu, 7 Jan 2016 09:50:11 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-TUID: je0x5TuPW/Je Hi Peter, On 01/07/2016 01:20 AM, Peter Crosthwaite wrote: > On Wed, Jan 6, 2016 at 7:13 AM, Eric Auger wrote: >> Current qemu_fdt_getprop exits if the property is not found. It is >> sometimes needed to read an optional property, in which case we do >> not wish to exit but simply returns a null value. >> >> This patch converts qemu_fdt_getprop to accept an Error **, and existing >> users are converted to pass &error_fatal. This preserves the existing >> behaviour. Then to use the API with your optional semantic a null >> parameter can be conveyed. >> >> Signed-off-by: Eric Auger >> >> --- >> >> v1 -> v2: >> - add a doc comment in the header file >> >> RFC -> v1: >> - get rid of qemu_fdt_getprop_optional and implement Peter's suggestion >> that consists in using the error API >> >> Signed-off-by: Eric Auger >> --- >> device_tree.c | 11 ++++++----- >> include/sysemu/device_tree.h | 15 ++++++++++++++- >> 2 files changed, 20 insertions(+), 6 deletions(-) >> >> diff --git a/device_tree.c b/device_tree.c >> index 8441e01..6ecc9da 100644 >> --- a/device_tree.c >> +++ b/device_tree.c >> @@ -321,18 +321,18 @@ int qemu_fdt_setprop_string(void *fdt, const char *node_path, >> } >> >> const void *qemu_fdt_getprop(void *fdt, const char *node_path, >> - const char *property, int *lenp) >> + const char *property, int *lenp, Error **errp) >> { >> int len; >> const void *r; >> + >> if (!lenp) { >> lenp = &len; >> } >> r = fdt_getprop(fdt, findnode_nofail(fdt, node_path), property, lenp); >> if (!r) { >> - error_report("%s: Couldn't get %s/%s: %s", __func__, >> - node_path, property, fdt_strerror(*lenp)); >> - exit(1); >> + error_setg(errp, "%s: Couldn't get %s/%s: %s", __func__, >> + node_path, property, fdt_strerror(*lenp)); >> } >> return r; >> } >> @@ -341,7 +341,8 @@ uint32_t qemu_fdt_getprop_cell(void *fdt, const char *node_path, >> const char *property) >> { >> int len; >> - const uint32_t *p = qemu_fdt_getprop(fdt, node_path, property, &len); >> + const uint32_t *p = qemu_fdt_getprop(fdt, node_path, property, &len, >> + &error_fatal); > > The _cell variant is now inconsistent with the regular _getprop. Can > we convert them both together and fix the clients to error_fatal? > (there are only 4 of them). Yes sure Best Regards Eric > > This would become the standard error_propagate pattern. > >> if (len != 4) { >> error_report("%s: %s/%s not 4 bytes long (not a cell?)", >> __func__, node_path, property); > > And this would also convert to error_setg. > > Regards, > Peter > >> diff --git a/include/sysemu/device_tree.h b/include/sysemu/device_tree.h >> index 269cb1c..4d7cbb9 100644 >> --- a/include/sysemu/device_tree.h >> +++ b/include/sysemu/device_tree.h >> @@ -45,8 +45,21 @@ int qemu_fdt_setprop_string(void *fdt, const char *node_path, >> int qemu_fdt_setprop_phandle(void *fdt, const char *node_path, >> const char *property, >> const char *target_node_path); >> +/** >> + * qemu_fdt_getprop: retrieve the value of a given property >> + * @fdt: pointer to the device tree blob >> + * @node_path: node path >> + * @property: name of the property to find >> + * @lenp: fdt error if any or length of the property on success >> + * @errp: handle to an error object >> + * >> + * returns a pointer to the property on success and NULL on failure >> + * in case errp is set to &error_fatal, the function auto-asserts >> + * on error (legacy behavior) >> + */ >> const void *qemu_fdt_getprop(void *fdt, const char *node_path, >> - const char *property, int *lenp); >> + const char *property, int *lenp, >> + Error **errp); >> uint32_t qemu_fdt_getprop_cell(void *fdt, const char *node_path, >> const char *property); >> uint32_t qemu_fdt_get_phandle(void *fdt, const char *path); >> -- >> 1.9.1 >>