Commit b0f21263 authored by Juergen Gross's avatar Juergen Gross Committed by Boris Ostrovsky
Browse files

xen/grant-table: remove gnttab_*transfer*() functions 



All grant table operations related to the "transfer" functionality
are unused currently. There have been users in the old days of the
"Xen-o-Linux" kernel, but those didn't make it upstream.

So remove the "transfer" related functions.

Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20220311103429.12845-2-jgross@suse.com


Reviewed-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
parent 982e4430

drivers/xen/grant-table.c

+2 −111
Original line number Diff line number Diff line
@@ -109,7 +109,7 @@ struct gnttab_ops { 
	void (*unmap_frames)(void);

	/*

	 * Introducing a valid entry into the grant table, granting the frame of

	 * this grant entry to domain for accessing or transfering. Ref

	 * this grant entry to domain for accessing. Ref

	 * parameter is reference of this introduced grant entry, domid is id of

	 * granted domain, frame is the page frame to be granted, and flags is

	 * status of the grant entry to be updated.
@@ -125,14 +125,6 @@ struct gnttab_ops { 
	 * access for this entry and return success(==1).

	 */

	int (*end_foreign_access_ref)(grant_ref_t ref, int readonly);

	/*

	 * Stop granting a grant entry to domain for transfer. Ref parameter is

	 * reference of a grant entry whose grant transfer will be stopped. If

	 * tranfer has not started, just reclaim the grant entry and return

	 * failure(==0). Otherwise, wait for the transfer to complete and then

	 * return the frame.

	 */

	unsigned long (*end_foreign_transfer_ref)(grant_ref_t ref);

	/*

	 * Read the frame number related to a given grant reference.

	 */
@@ -230,10 +222,7 @@ static void put_free_entry(grant_ref_t ref) 
 * Following applies to gnttab_update_entry_v1 and gnttab_update_entry_v2.

 * Introducing a valid entry into the grant table:

 *  1. Write ent->domid.

 *  2. Write ent->frame:

 *      GTF_permit_access:   Frame to which access is permitted.

 *      GTF_accept_transfer: Pseudo-phys frame slot being filled by new

 *                           frame, or zero if none.

 *  2. Write ent->frame: Frame to which access is permitted.

 *  3. Write memory barrier (WMB).

 *  4. Write ent->flags, inc. valid type.

 */
@@ -455,102 +444,6 @@ void gnttab_end_foreign_access(grant_ref_t ref, int readonly, 
}

EXPORT_SYMBOL_GPL(gnttab_end_foreign_access);



int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn)

{

	int ref;



	ref = get_free_entries(1);

	if (unlikely(ref < 0))

		return -ENOSPC;

	gnttab_grant_foreign_transfer_ref(ref, domid, pfn);



	return ref;

}

EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer);



void gnttab_grant_foreign_transfer_ref(grant_ref_t ref, domid_t domid,

				       unsigned long pfn)

{

	gnttab_interface->update_entry(ref, domid, pfn, GTF_accept_transfer);

}

EXPORT_SYMBOL_GPL(gnttab_grant_foreign_transfer_ref);



static unsigned long gnttab_end_foreign_transfer_ref_v1(grant_ref_t ref)

{

	unsigned long frame;

	u16           flags;

	u16          *pflags;



	pflags = &gnttab_shared.v1[ref].flags;



	/*

	 * If a transfer is not even yet started, try to reclaim the grant

	 * reference and return failure (== 0).

	 */

	while (!((flags = *pflags) & GTF_transfer_committed)) {

		if (sync_cmpxchg(pflags, flags, 0) == flags)

			return 0;

		cpu_relax();

	}



	/* If a transfer is in progress then wait until it is completed. */

	while (!(flags & GTF_transfer_completed)) {

		flags = *pflags;

		cpu_relax();

	}



	rmb();	/* Read the frame number /after/ reading completion status. */

	frame = gnttab_shared.v1[ref].frame;

	BUG_ON(frame == 0);



	return frame;

}



static unsigned long gnttab_end_foreign_transfer_ref_v2(grant_ref_t ref)

{

	unsigned long frame;

	u16           flags;

	u16          *pflags;



	pflags = &gnttab_shared.v2[ref].hdr.flags;



	/*

	 * If a transfer is not even yet started, try to reclaim the grant

	 * reference and return failure (== 0).

	 */

	while (!((flags = *pflags) & GTF_transfer_committed)) {

		if (sync_cmpxchg(pflags, flags, 0) == flags)

			return 0;

		cpu_relax();

	}



	/* If a transfer is in progress then wait until it is completed. */

	while (!(flags & GTF_transfer_completed)) {

		flags = *pflags;

		cpu_relax();

	}



	rmb();  /* Read the frame number /after/ reading completion status. */

	frame = gnttab_shared.v2[ref].full_page.frame;

	BUG_ON(frame == 0);



	return frame;

}



unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref)

{

	return gnttab_interface->end_foreign_transfer_ref(ref);

}

EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer_ref);



unsigned long gnttab_end_foreign_transfer(grant_ref_t ref)

{

	unsigned long frame = gnttab_end_foreign_transfer_ref(ref);

	put_free_entry(ref);

	return frame;

}

EXPORT_SYMBOL_GPL(gnttab_end_foreign_transfer);



void gnttab_free_grant_reference(grant_ref_t ref)

{

	put_free_entry(ref);
@@ -1423,7 +1316,6 @@ static const struct gnttab_ops gnttab_v1_ops = { 
	.unmap_frames			= gnttab_unmap_frames_v1,

	.update_entry			= gnttab_update_entry_v1,

	.end_foreign_access_ref		= gnttab_end_foreign_access_ref_v1,

	.end_foreign_transfer_ref	= gnttab_end_foreign_transfer_ref_v1,

	.read_frame			= gnttab_read_frame_v1,

};
@@ -1435,7 +1327,6 @@ static const struct gnttab_ops gnttab_v2_ops = { 
	.unmap_frames			= gnttab_unmap_frames_v2,

	.update_entry			= gnttab_update_entry_v2,

	.end_foreign_access_ref		= gnttab_end_foreign_access_ref_v2,

	.end_foreign_transfer_ref	= gnttab_end_foreign_transfer_ref_v2,

	.read_frame			= gnttab_read_frame_v2,

};

include/xen/grant_table.h

+0 −8
Original line number Diff line number Diff line
@@ -125,11 +125,6 @@ void gnttab_end_foreign_access(grant_ref_t ref, int readonly, 
 */

int gnttab_try_end_foreign_access(grant_ref_t ref);



int gnttab_grant_foreign_transfer(domid_t domid, unsigned long pfn);



unsigned long gnttab_end_foreign_transfer_ref(grant_ref_t ref);

unsigned long gnttab_end_foreign_transfer(grant_ref_t ref);



/*

 * operations on reserved batches of grant references

 */
@@ -162,9 +157,6 @@ static inline void gnttab_page_grant_foreign_access_ref_one( 
					readonly);

}



void gnttab_grant_foreign_transfer_ref(grant_ref_t, domid_t domid,

				       unsigned long pfn);



static inline void

gnttab_set_map_op(struct gnttab_map_grant_ref *map, phys_addr_t addr,

		  uint32_t flags, grant_ref_t ref, domid_t domid)