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Wysocki" , Tianfei zhang Cc: Dionna Glaze , Russ Weight Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" If a kernel module registers a firmware upload API ops set, then it's unable to be moved due to effectively a cyclic reference that the module depends on the upload which depends on the module. Instead, only require the try_module_get when an upload is requested to disallow unloading a module only while the upload is in progress. Fixes: 97730bbb242cd ("firmware_loader: Add firmware-upload support") CC: Luis Chamberlain CC: Russ Weight CC: Danilo Krummrich CC: Greg Kroah-Hartman CC: "Rafael J. Wysocki" CC: Tianfei zhang Signed-off-by: Dionna Glaze Change-Id: Ifac9513de2f58a5120d4c0a681e969cd71cd3c68 --- drivers/base/firmware_loader/sysfs_upload.c | 28 ++++++++++++++------- 1 file changed, 19 insertions(+), 9 deletions(-) diff --git a/drivers/base/firmware_loader/sysfs_upload.c b/drivers/base/fir= mware_loader/sysfs_upload.c index 829270067d163..97b0ae855b5f0 100644 --- a/drivers/base/firmware_loader/sysfs_upload.c +++ b/drivers/base/firmware_loader/sysfs_upload.c @@ -103,6 +103,10 @@ static ssize_t cancel_store(struct device *dev, struct= device_attribute *attr, if (fwlp->progress =3D=3D FW_UPLOAD_PROG_IDLE) ret =3D -ENODEV; =20 + /* + * Not idle, so fw_upload_start already called try_module_get. + * No need to get/put around cancel. + */ fwlp->ops->cancel(fwlp->fw_upload); mutex_unlock(&fwlp->lock); =20 @@ -164,11 +168,13 @@ static void fw_upload_main(struct work_struct *work) enum fw_upload_err ret; struct device *fw_dev; struct fw_upload *fwl; + struct module *module; =20 fwlp =3D container_of(work, struct fw_upload_priv, work); fwl =3D fwlp->fw_upload; fw_sysfs =3D (struct fw_sysfs *)fwl->priv; fw_dev =3D &fw_sysfs->dev; + module =3D fwlp->module; =20 fw_upload_update_progress(fwlp, FW_UPLOAD_PROG_PREPARING); ret =3D fwlp->ops->prepare(fwl, fwlp->data, fwlp->remaining_size); @@ -204,6 +210,7 @@ static void fw_upload_main(struct work_struct *work) fwlp->ops->cleanup(fwl); =20 putdev_exit: + module_put(module); put_device(fw_dev->parent); =20 /* @@ -238,7 +245,11 @@ int fw_upload_start(struct fw_sysfs *fw_sysfs) return 0; } =20 + fwlp =3D fw_sysfs->fw_upload_priv; + if (!try_module_get(fwlp->module)) /* released in fw_upload_main */ + return -EFAULT; + mutex_lock(&fwlp->lock); =20 /* Do not interfere with an on-going fw_upload */ @@ -310,13 +321,10 @@ firmware_upload_register(struct module *module, struc= t device *parent, return ERR_PTR(-EINVAL); } =20 - if (!try_module_get(module)) - return ERR_PTR(-EFAULT); - fw_upload =3D kzalloc(sizeof(*fw_upload), GFP_KERNEL); if (!fw_upload) { ret =3D -ENOMEM; - goto exit_module_put; + goto exit_err; } =20 fw_upload_priv =3D kzalloc(sizeof(*fw_upload_priv), GFP_KERNEL); @@ -358,7 +366,7 @@ firmware_upload_register(struct module *module, struct = device *parent, if (ret) { dev_err(fw_dev, "%s: device_register failed\n", __func__); put_device(fw_dev); - goto exit_module_put; + goto exit_err; } =20 return fw_upload; @@ -372,8 +380,7 @@ firmware_upload_register(struct module *module, struct = device *parent, free_fw_upload: kfree(fw_upload); =20 -exit_module_put: - module_put(module); +exit_err: =20 return ERR_PTR(ret); } @@ -387,7 +394,6 @@ void firmware_upload_unregister(struct fw_upload *fw_up= load) { struct fw_sysfs *fw_sysfs =3D fw_upload->priv; struct fw_upload_priv *fw_upload_priv =3D fw_sysfs->fw_upload_priv; - struct module *module =3D fw_upload_priv->module; =20 mutex_lock(&fw_upload_priv->lock); if (fw_upload_priv->progress =3D=3D FW_UPLOAD_PROG_IDLE) { @@ -395,6 +401,11 @@ void firmware_upload_unregister(struct fw_upload *fw_u= pload) goto unregister; } =20 + /* + * No need to try_module_get/module_put around the op since only the + * module itself will call unregister, usually when the refcount has + * dropped to zero and it's cleaning up dependencies to destroy itself. + */ fw_upload_priv->ops->cancel(fw_upload); mutex_unlock(&fw_upload_priv->lock); =20 @@ -403,6 +414,5 @@ void firmware_upload_unregister(struct fw_upload *fw_up= load) =20 unregister: device_unregister(&fw_sysfs->dev); - module_put(module); } EXPORT_SYMBOL_GPL(firmware_upload_unregister); --=20 2.47.0.163.g1226f6d8fa-goog