Recorded May 1, 1970 (George Harrison session), presumably improvised on the spot.
Plain 12-bar blues, with this little riff played a few times as an intro, and wherever there is an A:
Ab
: . . . : . . .
|-------5-----3-----------|-------------------------|
|(2)----------------------|-5-----3-----------------|
|(2)----------------------|-----------5-------2-----|
|(2)----------------------|-------------------------|
|-0-----------------------|-------------------------|
|-------------------------|-------------------------|
Or with this variation:
A
: . . . : . . .
|-------5-----3-----------|-5---3-------------------|
|-------------------------|-------5---3-------------|
|-------------------------|-------------5---2-------|
|-------------------------|-------------------------|
|-0-----------------------|-------------------------|
|-------------------------|-------------------------|
That’s just about all there is to say.