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iommufd: Add iommufd_ctx_from_fd()

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It's common to get a reference to the iommufd context from a given file
descriptor. So adds an API for it. Existing users of this API are compiled
only when IOMMUFD is enabled, so no need to have a stub for the IOMMUFD
disabled case.

Tested-by: Yanting Jiang <yanting.jiang@intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Link: https://lore.kernel.org/r/20230718135551.6592-21-yi.l.liu@intel.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Yi Liu 2023-07-18 06:55:45 -07:00 committed by Alex Williamson
parent 5c6de3ea73
commit 1c9dc07487
2 changed files with 25 additions and 0 deletions
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24
drivers/iommu/iommufd/main.c
View File

@ -377,6 +377,30 @@ struct iommufd_ctx *iommufd_ctx_from_file(struct file *file)
}
EXPORT_SYMBOL_NS_GPL(iommufd_ctx_from_file, IOMMUFD);
/**
* iommufd_ctx_from_fd - Acquires a reference to the iommufd context
* @fd: File descriptor to obtain the reference from
*
* Returns a pointer to the iommufd_ctx, otherwise ERR_PTR. On success
* the caller is responsible to call iommufd_ctx_put().
*/
struct iommufd_ctx *iommufd_ctx_from_fd(int fd)
{
struct file *file;
file = fget(fd);
if (!file)
return ERR_PTR(-EBADF);
if (file->f_op != &iommufd_fops) {
fput(file);
return ERR_PTR(-EBADFD);
}
/* fget is the same as iommufd_ctx_get() */
return file->private_data;
}
EXPORT_SYMBOL_NS_GPL(iommufd_ctx_from_fd, IOMMUFD);
/**
* iommufd_ctx_put - Put back a reference
* @ictx: Context to put back

1
include/linux/iommufd.h
View File

@ -54,6 +54,7 @@ void iommufd_ctx_get(struct iommufd_ctx *ictx);
#if IS_ENABLED(CONFIG_IOMMUFD)
struct iommufd_ctx *iommufd_ctx_from_file(struct file *file);
struct iommufd_ctx *iommufd_ctx_from_fd(int fd);
void iommufd_ctx_put(struct iommufd_ctx *ictx);
bool iommufd_ctx_has_group(struct iommufd_ctx *ictx, struct iommu_group *group);