[PATCH 2/3] libfuse: add kfuncs for iomap bpf programs to manage the cache

["Darrick J. Wong" <djwong@kernel.org>]

From: Darrick J. Wong <djwong@kernel.org>

Add a couple of kfuncs so that a BPF program that generates iomappings
can add them to the inode's mapping cache, thereby avoiding the need to
go into BPF program on the next access.

Signed-off-by: "Darrick J. Wong" <djwong@kernel.org>
---
 include/fuse_iomap_bpf.h |   28 ++++++++++++++++++++++------
 1 file changed, 22 insertions(+), 6 deletions(-)


diff --git a/include/fuse_iomap_bpf.h b/include/fuse_iomap_bpf.h
index 3e69fb33cbdd7c..1ff8f1831e12f6 100644
--- a/include/fuse_iomap_bpf.h
+++ b/include/fuse_iomap_bpf.h
@@ -149,6 +149,14 @@ fuse_iomap_begin_pure_overwrite(struct fuse_iomap_begin_out *outarg)
 	outarg->write.dev = FUSE_IOMAP_DEV_NULL;
 }
 
+struct fuse_range {
+	uint64_t offset;
+	uint64_t length;
+};
+
+/* invalidate all cached iomap mappings up to EOF */
+#define FUSE_IOMAP_INVAL_TO_EOF		(~0ULL)
+
 enum fuse_iomap_bpf_ret {
 	/* fall back to fuse server upcall */
 	FIB_FALLBACK = 0,
@@ -204,20 +212,20 @@ struct fuse_iomap_bpf_ops {
 
 /* Macros to handle creating iomap_ops override functions */
 #define FUSE_IOMAP_BEGIN_BPF_FUNC(name) \
-SEC("struct_ops/iomap_begin") \
-enum fuse_iomap_bpf_ret BPF_PROG(name, struct fuse_inode *fi, \
+SEC("struct_ops.s/iomap_begin") \
+enum fuse_iomap_bpf_ret BPF_PROG(name, struct struct fuse_inode *fi, \
 		uint64_t pos, uint64_t count, uint32_t opflags, \
 		struct fuse_iomap_begin_out *outarg)
 
 #define FUSE_IOMAP_END_BPF_FUNC(name) \
-SEC("struct_ops/iomap_end") \
-enum fuse_iomap_bpf_ret BPF_PROG(name, struct fuse_inode *fi, \
+SEC("struct_ops.s/iomap_end") \
+enum fuse_iomap_bpf_ret BPF_PROG(name, struct struct fuse_inode *fi, \
 		uint64_t pos, uint64_t count, int64_t written, \
 		uint32_t opflags)
 
 #define FUSE_IOMAP_IOEND_BPF_FUNC(name) \
-SEC("struct_ops/iomap_ioend") \
-enum fuse_iomap_bpf_ret BPF_PROG(name, struct fuse_inode *fi, \
+SEC("struct_ops.s/iomap_ioend") \
+enum fuse_iomap_bpf_ret BPF_PROG(name, struct struct fuse_inode *fi, \
 		uint64_t pos, int64_t written, uint32_t ioendflags, int error, \
 		uint32_t dev, uint64_t new_addr, \
 		struct fuse_iomap_ioend_out *outarg)
@@ -238,4 +246,12 @@ struct fuse_iomap_bpf_ops ops_name = { \
 	.name		= fancy_name, \
 }
 
+/* kfuncs; these require __ksym to link correctly! */
+int __ksym fuse_bpf_iomap_inval_mappings(struct fuse_inode *fi,
+		const struct fuse_range *read__nullable,
+		const struct fuse_range *write__nullable);
+int __ksym fuse_bpf_iomap_upsert_mappings(struct fuse_inode *fi,
+		const struct fuse_iomap_io *read__nullable,
+		const struct fuse_iomap_io *write__nullable);
+
 #endif /* FUSE_IOMAP_BPF_H_ */